Friend, when treating abscesses of the skin there are several components that need to be established:
1- The abscess must be drained, some times we actually leave drains in place so what we can flush the wound. If it is not drained then healing takes longer and it is more difficult for the antibiotics to clear the infection.
2- There should be appropriate antibiotics on board.
3- Pain management.
I understand you have spend a lot of money. But, unfortunately you are very limited as to what you can do at home. Your dog will need to be re-checked by a veterinarian to drain the abscess and dispense oral antibiotics and pain killers. Once the abscesses are opened this is what you do at home:
1- Do not let him lick the affected area. Pick up an ecollar (cone) in your local pet store or vet's office to stop him from licking/gnawing at affected area.
2- Pick up in your local pharmacy "Hibiclens" antimicrobial soap or chlorhexiderm scrub. Dilute 1-2 tablespoon for every cup of water. Use this mixture to flush the wound 2-3 times a day. The wound should heal from the inside out.
3- After flushing affected area as above apply a topical antibiotic like neosporin or bacitracin. Do this 2-3 times a day for the next 10-14 days.
Note: If cost is a concern look into your local ASPCA or Shelter where they often offer veterinary services at a lower cost.
My goal is to provide you with excellent service - I hope I've provided the information you were seeking, if you feel you have received anything less, please reply back as I am happy to address follow-up questions. Kindly rate me when you are done.