Question: After giving and receiving unprotected oral sex, the next day I noticed a purple-ish spot on the back of my penis where the skin is folded (the spot could have always been there and I just haven't noticed it until then). I looked up common STDs but it does not look like any I could find. The spot is painless, with a purple-ish appearance and with what seems like a bubbled raising, somewhat like a blister. However, I can mess with the spot and it never hurts and when applying pressure the bubbled spot gives no indication that it will pop (and I've been inspecting it a lot). Also, I can't really see the spot unless I move the folds of skin to reveal it and it only appears bubbled when I do stretch the skin. I also had a sore throat and body aches with a fever the next day, and when I visited my doctor was given antibiotics for strep throat (even though my rapid test was negative). (The last time I had strep, however, both my rapid test and throat culture came back negative but I definitely had strep because I ended up having Scarlet Fever since I was allergic to the toxins, too.) She also looked at the spot and suggested that it might just be a pinched or irritated vein on my penis, but didn't seem too sure, and I can't find pictures online looking the same. What could the spot potentially be, an STD, or just an irregularity? It seems unchanged for the past 3 days. Also does my sore throat potentially indicate some viral infection related from oral sex instead of strep since my rapid did come back negative?

Would a viral infection also cause my tongue to have a yellowed look as well? I have only been taking the antibiotics for two days, but they have seemed to help, unless I'm just getting over the virus quickly (since antibiotics shouldn't help with a virus). Likewise, could it be some other bacterial infection (potentially connected to a STD) that the antibiotics I'm taking would help with too?