When I had english bulldogs, I'd (hah, THEY'D) regularly get bumps, hives, rashes. If your vet didn't prescribe or recommend something, find another vet! My vet prescribed Betagen and Maleseb spray or pledgelets for use on rashes and bumps. I just had those in the cupboard, and I'd try them first, before going to the vet for every new thing. I think Maleseb you can buy on your own, but Betagen is prescription. Almost 100% of the time one of those would fix the rash. I understand the cream frenchies have more sensitive skin, from what I heard, and are more prone to allergies. Find a better vet, I would say. I hope that your baby is feeling better by now, but plan ahead because these things will happen!
Karla