honey this is herpes: small red bumps that may develop into blisters and open lesions. These “bumps” appear at the site of infection, which may be in or around the vaginal area, the cervix, the penis, urinary tract of both men and women, and around the anal opening, buttocks or thighs. Sores also may appear on other parts of the body where broken skin has come into contact with HSV. Over a period of days, the sores become encrusted and then heal without scarring.
and this is syphilis: The primary stage of syphilis is usually marked by the appearance of a single sore (called a chancre), but there may be multiple sores. The time between infection with syphilis and the start of the first symptom can range from 10 to 90 days (average 21 days). The chancre is usually firm, round, small, and painless. It appears at the spot where syphilis entered the body. The chancre lasts 3 to 6 weeks, and it heals without treatment. even though it appears as if it is healed it's not you know why because it is still in your blood and it will start the secondary phase
you said its painless and it is one ulcer so it might be a syphilis you need to do a vaginal swap and if the ulcer vanished you need to do a blood test its not safe if it went to the blood -----> clotting block the blood veins