my dog has multiplying blisters on his chin

[KnightofZero]

My dog has some multiplying blister on his chin and more show up slowly.  the vet said she was not sure what it was it could be bacteria or allergies maybe even viral but it doesn't really show any signs its viral. I will take him to get a biopsy but payday is a bit away, if anyone can help me help him for now I would be really thankful. He is a Lab mix, and is 5.5 years old, he has never had allergies before. they gave him a antihistamine and keflin shots. and prescribed him Cephalexin 500mg 2 every 12 hours and Benadryl 100mg every 12 hours. He has been on his medication for 1.5 weeks but the bumps are multiplying still and enlarging. At first it was just one big one and then more started to appear and keep appearing they were originally only on his lower lip but now he has some on his upper lip, they are not on his gums or on/in his nose. I keep them dry but they tend to get shiny or a little bit of bland yellow puss. it doesn't hurt him when i touch the dry parts but if i touch too hard on the puss he does not stand still since it hurts him. also idk if this is helpful but I live in las vegas a desert region and it has been windy lately and a lot of bugs have been coming out especially mosquitoes and spiders. My sister just moved in and she has 2 dogs, and 2 rabbits.

[Margot49]

Hope you can get a definitive answer.  Skin issues can be so hard to figure out.
Please do come back and update.  

[KnightofZero]

Yea any of those is what I was thinking Thanks. I had a plastic bowl but took that away. I'm taking him in for a biopsy this weekend. thanks again.

[Margot49]

Are you feeding out of plastic bowls?  If so, use stainless steel or ceramic instead.
Could be canine acne.
Could be problems with the hair follicles
Could be staph.
Try to keep the area washed and dry.
If it gets worse, best to have your Vet check it.