There was a risk though it is a little more then a low risk I would say if he has symptoms to be seen within 24-48hrs for a lesion culture.
You should avoid oral sexual contact and kissing when you have a coldsore present. Wait for the skin fully heals to avoid the risk of transmission.
Also if your boyfriend hasn't been tested to know his own status he can have a type specific igg hsv test. He may already have HSV-1 himself and not even know it.
Also while performing oral on him I made sure his genitals had no direct contact with the scab. Does that matter?
No that doesn't. The virus isn't just contained in that one spot. The only way it would have been safe is if he used a condom.