Is it worth trying a strongly antiseptic mouthwash? I agree a dentist is the real solution, but it might help. Somehow aantiseptics have gone out of faour, whilst antibiotics are being over prescribed.
I found that quite helpful in dealing with minor gum infections BUT it does tend to dye your teeth brown. My current dentist has recommended a toothpaste which contains the same antiseptic but doesn't discolour the teeth: Elgydium