First year bee keeper here. Installed them back in May from a nuc. About 3 weeks ago we added a medium super (with an excluder) as they were really doing well. Today while Doing a bi-weekly inspection (nice sunny day, around 1pm),everything was going great - bees seemed calm, doing there thing. I got through inspection of the super which is drawn out and filling with honey. Really nice.

After A light smoke, I moved to the hive body. I made it to the second frame and just as I was pulling out the frame, the bees flipped out. They were pissed and coming after me. I managed to get the hive all back together and hi-tail it out of there but not before getting stung in the head through the vale.

Previously the bees were very tame, I’d only have a couple around me as I inspected them. Today was like a completely different hive. Something pissed them off but I’m not sure what. Any insight as to what I did wrong, what I could do better?

Thanks!

Edit: I’m in Western NY