Cut in my vaginal opening. causes and solutions

Genital ulcer: If there was no obvious injury (e.g. traumatic sex), the genital herpes is the most common cause of genital ucers or "cuts". Syphilis also is common in your country, if at risk. Yeast infection (thrush) if there also is a lot itching/irritation. See a doctor ASAP for testing and treatment, if available to you -- the sooner the better for accurate diagnosis and effective treatment. Good luck!