I feel like the basic concept is solid, but that a variety of little issues make this cover a bit hard to read.
Before I get into the drawing itself, I feel like the text style, size and placement is good, but it'd look even better if you used a font rather than doing it by hand. Hand lettering is hard to do well, and if there's a font that looks similar to what you're after, it's usually best to use one, and just save hand-lettering, (or messing around with the letter shapes in a design program) for when you want something really specific. If you could look for a chunky font and do a stroke effect, it'd look more polished.
Going onto the images... It took me a while to work out what was going on here, and for a minute, I thought I was looking at a wrestling mask. It's easier to go through in bulletpoints if that's okay...
- The mottled texture on the colour is a bit distracting. The areas of lighter and darker colour are too large to make it look like a deliberate texture, so they read almost like shading, but since they're not placed where light and shadow would fall on the stage and curtains, they make it hard to tell we're looking at a stage and curtains.
- Putting rivets onto the borders around the cutaways on the top left and right is confusing because it makes it look like they're really there, not like we're seeing three different angles and a split-screen or montage. It's a bit confusing visually, like the curtain has two big portholes in it.
- The angle on the stage isn't consistent with the angle of the character or the mic stand on the stage, which makes the perspective feel off.
- The size of the stage and the stage being grey makes a dominant colour of the cover a boring neutral mid-grey. There could maybe be a more unified colour palette here, because the pink in the top right clashes a bit.
That said, there are things I like here. There's a strong sense of the comic's general identity and style, and the cover gets across what the story is about really well. I also like how the small figure on the large stage really effectively conveys how young and nervous she is. Overall, the main areas for improvement here are less on the concept and composition, which are pretty strong, and more on the polish of the execution.