Thanks... and how about kissing after oral sex was performed? Is there a risk of HIV infection?
Lots of resources on this site about what you can and can't catch through oral sex. But in summary:
1) It is theoretically possible, but extremely unlikely
2) I'd like this to be backed up by an expert - but I'm going to say no. Epididymitis can be a symptom of some STDs, but this results in very significant pain - not a red colour of the testes.
3) No, your risk is negligible