Fourteen-year old Daniel Venture has been cursed his entire life with pus-filled blisters. He's already swallowed hundreds of pills and saw twenty seven doctors. Nobody knows what causes the blisters or how to cure them.
Doctor number twenty eight knows. (I like this hook. Definitely gets me interested.)
If Daniel undergoes the treatment she offers, he might get back to school and make some friends, go to the pool, and stop wearing long-sleeved shirts to hide his boils. But the doctor asks too many questions about his mother, and urges him to sign the contract without the presence of a legal guardian. (As someone else mentioned, this is really sketchy and illegal, though if done well in the story, could ratchet up the tensions nicely.) But Daniel wants to be cured. Just as he's about to agree, a snake slithers out from her hair - he stifles a scream and makes a run for it, problem solved. (This last bit sounds a little awkward. Consider rewording it.)
But when his mother won't pick up her phone and the receptionist at her work says she has never worked there, Daniel realizes he must return and talk to the doctor again. The doctor confirms she has indeed kidnapped his mother, and if Daniel wants to see her, he must pay.
Not with money, of course. The doctor wants his eyes. (I like this bit of bargaining. It also establishes the stakes for the character)
Once Daniel makes that sacrifice, he's being transported to a parallel world where his mother is being held hostage. But the doctor disappears and his mother is nowhere around.
Though he's practically invalid, Daniel is not a person that would give in. If he is to find his mother, Daniel will have to dig deeper into his family history, and choose between risking death and saving his mother. (A bit vague, we don't know why he needs to dig into his family history or how his life is at risk. Use more specifics to make it clearer.)
Combining elements of mystery, RED EYED DANIEL is a YA paranormal, complete at 93,000 words.
Overall I like the idea behind the story. It's intriguing, but some of your query is a bit on the vague side. Hope this helps!