I have a 15week old female pitbull puppy she is around 40lbs her name is Bella...she had been outside playing and started up the steps on our back porch where I was setting at and, she got about 2 steps up and started screaming and crying out. I ran to her she was acting as if she was trying to get on up the steps and couldn't as if she was stuck or something. As I got to her I seen she wasn't stuck or anything like that but was still yelping and crying. I picked her up took her in to see what was going on with her and the only thing I could see was a red spot on her inner back leg in the thigh area on the muscle area. I had my husband set with her while I went out to look and I did see 2 wasp flying around by the steps. I came back in and told my husband and got her a generic Benadryl and gave half of it to her. Since this has happened she's still not walked on that leg. She walks around but holding her legs up and not letting it touch the floor at all. It's been about 9hrs since this took place.. in the 9hrs her complete amount of the genetic Benadryl intake totals to just 1and 1/2 pills. She now has a reddish pink color like rash on part of her belly thats closest to the leg where she was stung. What should I do? She still won't put any weight on her back leg and her vet doesn't open again until Monday morning.