Hello everyone, specially @savage35667 there's nothing to worry about.
This is not any kind of STD or STI, this a fungal infection. It's a variation of Tenia crusis, a common fungal infection. It should not create any complications, but there are some medications for this also. If it feels necessary, you can visit a doctor (or get online consultation) and they will prescribe you some creams and shampoo based on your medical condition and history. It may come back again and again if you do not use those medicines properly of stop using halfway.
BTW keep yourself away from unhealthy sexual relationships to be protected from any possible STD that can attack you on future.
Have a nice day and wish you a good health.