My dog got bit by a lot of ants and her feet and lags are swolen and can i give her clindamycin 300 mg,?

Since Clindamycin is an antibiotic, it won't do anything beneficial for your dog. If you're going to do anything, I would suggest calling your vet. If you can't afford to take your dog to the vet, ask them about the dosage of benadryl your animal would take for this problem.