Will my Pugs Die from chocolate?

My two pugs just got to three whole bags of M&Ms and Two Hershey Bars =O I am scared that they will die because they are not throwing it up or anything. It happened a week ago and they look fine but i am still not sure of it will cause any further damage to them. One of them got a brown skin flap on their tummy. Looks like it is growing, so we took it to the vet and they tested it. The results were: Non cancerous! BUT IT IS SO BIG! Any way, is chocolate not poisoness to only pugs?