Hi I Had Unprotected Intercourse About 8 Days Ago, Not

Hi
I had unprotected intercourse about 8 days ago, not full sex just half of the Penis went in the Vagina, I stopped because she started bleeding of menstrual cycle, there wasn't any blood on my Penis as far as I remember but still I straight went to the wash room nd cleaned it with water, but still I was worried about any kind of STD, yesterday I felt a nodule type thing on right side of my Penis nd today I checked it nd it is I am afraid Chancre like structure or nodule m nt very sure abt it, the problem is I am worried abt it, what it could be and what may it lead to? nd what should I do please tell me