No. the Benadryl is if he is having a severe reaction, like breathing very fast, skin-crawling and rippling, anaphylaxis symptoms. Now he just needs time and a future vet check if it doesn't go down in a few days, and the sore getting better. An insect sting can take several days to subside. The sore COULD be from the point of injection or him biting himself when it happened, or because of the swelling. If it goes beyond a few days it could be teeth problems, but I doubt it. as long a she isn't in any distress, hiding, pawing at his face, etc. all is well......
I feel so bad for not replying sooner. Apparently I had typed up a message, never hit send.
Sammy's lip has completely gone down! We didn't need to take him to the vet, it went down pretty instantly. Thank you all for helping and keeping me sane!