Why is my hair thinning so much ?

it may just be hormonal.. as you get older.. even though you are 17 your hormones are changing and always will.. your body may just be going through a transition.. even though you are not stressed maybe your body is? it could be breakage too.. which could be from the burn. if it has grown out now though not too sure why it would break off but that can happen. if it gets worse i would recommend going to the doctor. for now just baby it, and it you are not already takin it i suggest biotin.. its vitamin b7 and really good for the hair skin and nails. hope this helps! :)