Your follow-up question should have been asked as a follow-up comment here. I deleted your new thread.
Oral sex is not a risk for catching HIV, or at least low enough it can be totally disregarded. And as I already said, the other events were risk free as well. For more discussion of HIV risks with oral sex, go to the HIV Prevention forum and use the search function.
That will be all for this thread, and please don't start any new questions related to this exposure, either here or on the HIV forum. There is nothing you can add that would change my opinion or advice.
Welcome to the forum. This site is fine; since your concern is STDs other than HIV, your question could have been either here or the HIV forum.
Oral sex carries low risk for all STDs; not risk free, but with a lot lower likelihood of infection than vaginal or anal sex. In any case, no STD can cause symptoms in under 24 hours; 2-3 days is the minimum. Therefore, the red mark on your penis cannot be due to any infection from your partner's mouth. Your first impression probably was correct: most likely it resulted from minor trauma during the sexual exposure. The other expossures you describe -- hand-genital contact, anal fingering -- are entirely risk free.
If the red spot has cleared up and you have no other symptoms like penile sores or discharge of pus or mucus, you can be quite sure you weren't infected. However, if you remain concerned, I suggest you visit a your local NHS GUM clinic for examination and perhaps STD testing; or you could find a private clinic. (If you are in or near London, consider Freedom Health, an excellent private sexual health clinic.) Either optins will offer expert care, where you can be completely frank about your sexual exposure. Trust me: they have seen it ALL before and won't bat an eye at your experimental exposure with another man. And that's probably all it was -- this isn't something to beat yourself up about.
I hope this helps. Best wishes-- HHH, MD