Vaginal bleeding

I had gotten a swollen vagina when with a guy. It was swollen on just one side. I had figured it was from roughness and not enough lubricant. I let it be and go down by itself. I continued the next day, when I got home my underwear was stuck to my vagina and wouldn’t come off. I had to slowly rip it off. When I checked the inflammation was gone, but I still had discomfort and redness. I then saw blood on my underwear and all over my vagina. I saw another post about swelling on here. It’s not my period. Is this okay? Why did I bleed? Could this be a cyst? Or could this just be an infection that needs antibiotics?