90s Teen horror - boyfriend deal with demon

Question

Hi I'm trying to remember the name of a teen horror book from the 90s that featured a girl whose boyfriend ultimately turned out to have done a deal with a demon for her soul. I think turns out she is adopted and at one point she has red paint tipped on her in a shower and a friend mentions her hair is "strawberry blonde with real strawberries". I thought it was point horror or something like that but I've looked online and none of the covers seem to match. The cover was dark with an artists palette with a demon's pointy twisted thumb tipped with red. Thanks

Answer 1

I did a google books search for this, and you almost had it. Just needed to remove an "e" --

"What's this?" Chiku grinned. "A new look? A strawberry blond with real strawberries?"
"Don't even try to joke about it," Sharon said darkly. "This was its latest attack on me." She told her friend about the new dream and the blood in the shower.

It is I. O. U. by Nicholas Adams. The same author did a series called Horror High, but this doesn't seem to be part of it.

Here's some other bits of evidence:

• An Amazon review says "her parents have been keeping a dark secret about her birth" (hint about adoption?)
• Same review says " ideal for teens who enjoy scary books about nightmares, demons, and curses" (emphasis mine)
• And the covers (I found two) both do have the artist's palette, and one (the one at https://www.goodreads.com/book/show/1458621.I_O_U_) has the twisted thumb
• Finally I found out that Nicholas Adams is (in this case) a pseudonym for John Peel. And on his website (http://www.john-peel.com/pb/wp_e8dfd6a3/wp_e8dfd6a3.html) I found a good description of the book which confirmed that

  Sharon's been having bad dreams that she's being hunted by a demon. It turns out that her dreams are quite accurate, and that [redacted] sold her soul to it before she was born.