Welcome to the Forum. I suspect the discomfort you report immediately after your experience was related to the broken blood vessels you mention. What you had was essentially a bruise.
I do want to clear up something about your risk however. Following oral sex your major risk is for gonorrhea as you point out, and nongonococcal urethritis (NGU), not chlamydia. Chlamydia is almost NEVER transmitted by oral sex while NGU is pretty common. The test to confirm or diagnose NGU is to look for white blood cells in your urine or in a swab taken from your penis. If those were negative however (and looking at some of your other posts on the STD Prevention Community site, that appears to be the case), you are most unlikely to have acquired an STD through this exposure.
One further comment. the long period between your symptoms and their recurrence also make NGU or any other STD unlikely. When symptoms are due to recently acquired STDs, they tend to stick around, sometimes varying in intensity but not c coming and going as you describe.
Bottom line, there is little reason from the information that you describe to worry about an STD from receipt of oral sex 3 weeks ago. I'd advise you to "shake off" your concerns (pun intended). EWH
Yes. Sometimes when we have a cocnern such as yours there is a tendency to detect sensations and findings which have not been noticed inthe past. I suspect this may be going on in your case. EWH
Thanks for the response Doctor. So your best guess would be that the symptoms are all in my head?