You keep asking all these no risk questions, so here's how STIs are transmitted -
* Unprotected oral, vaginal or anal sex - actual penetration in the mouth, vagina or anus
* Direct, unclothed skin to skin contact of the mouth, genitals or anus - think rubbing or grinding without clothing. This usually requires time and friction, usually the kind associated with intercourse. A brief touch is not going to transmit anything.
This means mouth to genitals, genitals to genitals, or genitals to anus.
A syphilis rash isn't on the biceps and shoulders.
The others are right (and you've now heard from all of us). Your anxiety is the biggest problem you face here.
So, in looking at your posts, you have several and they are ALL no risk. I think the real problem here is your anxiety. My recommendation is to begin working on this. Anxiety is a treatable condition. Reassurance seeking each time is not helping you. You have to work on the anxiety to move past this.
So after some googling some updates:
He had no sores on his penis. He did have acne on his torso, so it could be that.
The mystery bump on his arm doesn’t look like how it presents.
Can someone please answer the hypothetical risk of that bump on his arm was indeed a chancre?