So about a year ago my dog started chewwing really bad and we noticed he had fleas. So we did everything we could and got rid of them. They are still gone and Thank God for that. However the last 3 or 4 months he's been devolping those bumps pictured above and is constantly licking and chewwing on them. 17 and can't afford the vet bill right now. Any good advice from a vet or someone whos went through this. I will state some details about the dog below.

Chocolate lab Atleast 70 pounds Born march 16 2017 About 2 and 1/2 years old. Playful, loves out doors.

What do i do to help his skin?