Dogs cannot get chicken pox so whatever is affecting your dog didn't come from you having chicken pox. Have you recently changed your dog's brand of food? It's possible that it could be a food allergy (or another type of allergy) but if everything has remained the same in the dog's routine and she has developed this rash, then my guess is that it could be a staph infection. Dogs develop staph infections fairly easily and the belly and insides of the hind legs are the prime target areas. The most common causes of staph infection are stress, a weakened immune system, allergies (flea bite allergies, for example) and hormonal problems (ie hypothyroidism).
Ghilly
As far as I am aware, dogs cannot contract chicken pox. This sounds much more like a food allergy rash to me. You will need to get your dog to a vet so they can prescribe an anti-inflamitory and an appropriate antibiotic. Can you list what you are feeding your dog? If it includes beef or chicken, I would stop feeding them, as they can be the root cause of allergies in some dogs. Try white fish and boiled white rice or if you are using a tinned dog food, aim for another brand where the content is mainly white fish. The problem for the future will be to try to identify what type of food your dog may be allergic to - and that could well have to be by trial and error. After your dog has been treated and you are sure the rash has cleared up, you might try feeding her a little chicken on its own - then wait and see if the rash starts to reappear. If not, then you know you are safe with chicken. After another short while, try testing beef in the same way - and so on until you identify the problem. Tony