Your dog might be having a skin infection or allergic reaction that might have been caused due to food or some bacterial infection.
Regularly deworm your dog. It is very important to deworm your dog regularly for its betterment.
You are right the bumps might be because the dog is scratching and biting itself due to itching.
Check your dog regularly for the presence of ticks. Remove them if you find ticks on your pet.
As this is skin infection with usage of tablet and lotions also it takes about 2-3 weeks for curing.
Deworm your pet with store available deworming tablet.
Use Shampoo CLinar M.
Make sure you lather the shampoo and let it sit for 15 min. Wash it thoroughly.
IMP- Make sure shampoo doesn't go in eyes nose mouth. Dog should not lick the shampoo at any cost.
Use tablets
Tab Lixen 300mg morning and evening for two weeks.
Tab Wysalone 10 mg morning and evening for two weeks.
Use Ointment Staphben on the bumps or worsened wounds on pet's body.
Next Steps
Feed your pet with better nutrition like eggs, milk, curd, chicken etc
Health Tips
If you want your pet coat to shine and be healthy you can use syrups like Syrup Vitabest derm 7ml in morning and evening.