It's visible, but still can be a bit hard to see (if the phone is really dim).
I have a similar issue with this, but I feel the scenario and the character's qualities won't be changed, so I played with the shading as a way to sculpt his face for it to be more defined/visible.
When the time comes for us to see your comic, we can see how visible she is within her environments.
Proud of you! :^)
Her whole face is visible, but still pretty hard to see - though my monitors are never at full light/bright settings, so all the darks start to blend together the dimmer it gets. 
Perhaps a more contrasting color in the lines or highlights, since they look very similar at first glance. This can be either:
I did a test drawing playing around with brighter colors for the skin (same dark as your drawing) and lighter highlights for example. The eyebrows are still hard to see. . . 
Alright. Take...I don't know...6 or 7 lol.
Could anyone tell me how well they can see Mora's features in this picture?
It's an improvement, but I still find it hard to see. The overall values of your color palette are still too close to ech other I feel.
All of your colors exist in this bottom space of value scale which makes them all blend together.
The red in the dress is the biggest outler, but it helps that it is contrasted againt the blues. But it too is really really dark.
As an example, the color palette I use in my work has this range on the value scale
I agree with KevinReijnders, yes improvement 
but the hues are too close in darkness to see clearly.
It feels like the character might be wandering around in the dark. . . same suggestions as before.
Additionally I want to show some quick edits. All I did was change the contrast on your drawings (ironically I had to lower the contrast, because the colors are just that close to each other.)
Both characters became instantly more readable, without losing that deep dark skin aspect of them.
Now in both examples you'd probably wanna tweak the saturation somewhat so it blends more harmoniously with the rest of the colors.
If you actually wanna start practicing shading and rendering as a whole, I would definitely advice to use lighter colors as your base, otherwise your shadows will drown out what little contrast you have.
Did a very quick and dirty render. Fun little detail about this one, the shadows on my edit are your original colors.
Ok Here are my big tips no 1. contrast, I think that because she's always in a white void is whats making her skin tone blend with her hair. her incredibly bright white clothing also contributes to this, so consider putting her in a grey void and switching up the colour scheme. no. 2 because the hair is the main thing thats conflicting with her skintone, consider hairstyles where it wont intersect with a lot of her body. I like her long flowy hair but it does make it difficult to see her arms and neck
as part of my switching up the colour scheme, i did darken her eyes. I assume that she either has magic abilities, or cataracts/another visual shorthand for blindness. given the magic, just use a darker blue. given the blindness, she can have another vision imparing condition that doesn't effect how her eyes actually look. most blind people don't "look" blind, I'd advise giving her a cane or a seeing eye dog, as it still serves as a shorthand but doesn't mess with the contrast. (plus doggie!)
yeah, unfortunately, my app glitches and won't let me color my bgs, ever without crashing. Also interestingly, her eye color has nothing to do with magic or blindness, just her gene combo.
I wouldn't say there's a strict rule to how much contrast you should go for. It's kinda dependent on what the situation requires. I think a basic rule of thumb to follow is the bigger the contrast the more readable your design.
But I would add to that, that there are 3 dimension withing color you can play around with to create interesting contrasts.
You've got Hue:
You've got saturation:
And you've got value:
You can use the contrasts of all three of thee individual dimensions to create a dynamic and readable design.
Edit:
I wanted to add a practical example of my own work. Here's Kyara, each time adding 1 of the 3 dimensions, starting with hue. She's basically just 2 colors, blue and orange.
2nd Edit:
Because we're on the topic of dark skin, I wanted to showcase how I solved it in my own color palette. Since I think that works better for me than trying to do edits. I used the same Kyara drawing and only changed the skin and hair tones. Here's a flat and a rendered version, to show that you don;t need to rely solely on renders to make a readable design.
You can always check how things work in the real world, no matter how dark a skin is, it must reflect light, it can still preserve its dark tone, but be fully glowsome (and not washed out).
1
The darker the skin, the more bright the glows must be.
Without light, even a peson with white skin will appear fully black 
Light is the key, follow the light \o/
I am not sure if you are going for realism or fantasy with her skin color. But you could push it to be a bit warmer.
I also think that her dress should be a lighter color so it doesn't blend in with her skin color.
Dark skin is all about highlights and undertones essentially. I know I mostly write on here but I do art and had a comic previously with a cast of all POC characters. The key is really the highlights and undertones (warm, cool, neutral etc). All skin reflects light and in darker skin tones that reflection can be more apparent. Highlighting on the nose, the cheekbones, the high points of the face and body adds dimension.
Watching makeup tutorials is also a good study. Where they place highlight on the face, where the contour is, it's kind of helpful for an artist when you're looking for the high and low points of the face to figure out where that might typically be.
Ah. . . I did not learn color theory in any formal matter, so I do not know. 
I just keep messing around, messing up until I find color combos I like looking at.
If it is difficult to see things color-wise, you can try checking contrast with a little paint pallet like I been adding to the test drawing. It might help (or it might do nothing)
* If you can easily see all the colors are comfortably different -- bee's knees! 
* If some colors are blending in or just look bad together, you can change them until you see a combo you like. 
