Swelling/Discomfort/Dragging/Scratching

My small dog has begun to itch, and be in discomfort today. He hasn't been sitting still for very long as he gets up and drags his behind or scratches. I looked and I saw slight swelling of the genitals. I also saw a small red patch. I'm thinking a bug bite, but see no obvious marks of one occurring. I gave him a tad bit of Benadryl. I don't believe it is doing much of anything. Allergic reaction was mentioned, although he has not eatin anything.

Your dog needs to be seen by a vet ASAP.

Agreed. You dog is in obvious discomfort and needs to see a vet. Enough said.

I agree see the vet it might be infected anal glands but deal with it immediately so it does not get worse and cause your dog more pain.