Sure, my insta is @kelplessseas.
With hairspray, you just spay it and leave it to sit, it dulls the contrast so that highlights w/ chalk and deeper tones w/ charcoal will be washed out. I did this a couple times in art class. With acrylics or glue you just paint it on over the sketch. Use a clear glue like modgepodge or some other PVA and leave it to sit and dry completely. making these pages wet later will reactivate the glue. Acrylic works pretty well but can also flatten the sketch by skewing the hue range.
You can also go over the sketch with colored pencil or watercolor. But both can smear lines.
Generally I'd just reccomend switching to sketching with pens or colored pencils, which don't smear and build line confidence while also insentificing you to work quickly. Which is better for making comics. And if ye fuck up, stickynotes! Or liquid paper or whatever man (if i dislike a sketch i just write "eh" next to it and move on). I like sketching with pencils but I tend to be happier with my ballpoint sketches these days.