I'm sure this will sound totally ridiculous...
70% of me believes I saw this movie, but the other 30% is wondering if maybe it was just a really strange dream.
Now for what I remember about this:

There's a creepy place, some type of warehouse or building. I think it's a kid and his older sister, he end up being the one to go in. For some reason it scares him so bad it turns his hair white and makes it fall out. He tries to hide this by using glue to attach a wig to his head. I think it was at a soccer game or some sport where an older kid, bully type, pulls this wig off exposing his baldness. Sounds pretty weird, eh.
It's got me to the point where I'm asking the internet. Perhaps someone saw it and knows what the title is...
Or maybe you had the same dream as me and could comment. Ha.

Does he grow his hair back with peanut butter?

The peanut butter really struck a chord. I believe he did try and grow his hair back with peanut butter. I can remember them slapping a big ol wad of peanut butter on his head... I think

I think that would be the Peanut Butter Solution then or something like that. I think the peanut butter made his hair grow long.

Yep the peanut butter solution is it.

Two ghosts show him the recipe and it involves peanut butter and flies and whatnot, bbut they put too much flies and his hair grows really fast and really long.