I know how te feel...it's tough because I had (still kinda do)that problem. Have te tried getting some nail polish that burns your mouth/taste nasty? o how about chewing gum? Well, I just bite my nails when my hands o fingers are left alone for a while. If it's that try to keep your hands busy (read,write,play..stuff like that)
i cant stop biteing my nails ive tryied nasty nail polish and hot sauce on my fingers(it almost helped but i like hot sauce so that made me bite my nails more) even doing stuff like Leggere i bite my nails!!!!!!!!!!!!