First off DO NOT put bp on your head! It will die your hair blond almost certainly plus your scalp may not be able to tolerate it as much as your face can. Second of all is it really noticeable, like people can point it out or is it just hurting and only you know about it. If the latter then i reccomend just using a gentle shampoo, you know the type fragrence free, colours free etc. Something with alot of fruit in usually does the trick. Also try adding some apple cider vinegar to your shampoo, it makes your hair really smooth aswel as helping against those dreaded pimples. Hope this helps
EDIT : just read again and you say its bad enough to see when your hair is really short, well simple answer is dont let it get too short. Next time you get it cut go up 1 or 2 numbers so its not as short!