washing up after sex doesn't reduce your risk of a std. Std's don't lay on the skin to work their way down into the body to infect you - they are transmitted during the sex act itself. Trying to clean with soap inside your urethral opening does far more hard than good too - don't do that again in the future!!
this was mostly protected sex and not really a risk. in the future, when your pants are off, a condom should be on. unprotected oral is low risk but not low risk and should be avoided when it's not a regular partner.
whatever is going on in your armpit and upper body are not related to this encounter. follow up on symptoms with your provider.
the only std testing that was accurate 1 week post encounter was gonorrhea, chlamydia and ngu. you need to wait at least 6 weeks post encounter for syphilis testing and 3 months for herpes, hiv and hepatitis testing.
Thank you Grace for your answers.