HELPP!!! I'm really worried about thiss:(?

ok, so I'm 15 and I've been since a young age, (this is really awkward and weird) but i used to use my hands (like in fists) and I stopped a while ago but it left lk kinda marks (that lk stretch out the skin) in the inner part of my upper thighs ..and they haven't gone away and it's really embaring ..especially when I have to wear a bathing suit and stuff...so please heeelllppppp!!!!!!!!!!:(:(:(:( (note:these are not stretch marks)