Skin nodules can be due to a tumor, granuloma, abcess, or cyst. The mass you are describing may be an infected granuloma or cyst, and I recommend that you take your dog to the veterinarian within the next few days for appropriate diagnosis and treatment, starting with microscopic analysis of the fluid +/- biopsy or surgical removal depending on initial lab results.
Kimberly Coyner, DVM DACVD
I agree with Dr. Coyner. Please see your veterinarian and be aware that abscesses from the teeth can appear above the tooth under the eye as well. Your veterinarian can better explain this relationship and determine if it is of skin or mouth origin.