this is white tigers recipe for similar problems. if you can reach the area with a cotton swab or cotton tip you can try this.
Mix 4 drops each of tea tree oil & lavender oil with 2 teaspoons of vegetable oil.
Apply a light coating of this mixture to the effected areas with a clean finger or cotton swap.
The sores should clear up within 3 to 5 days, and the sores will probably not come back again.
you may also want to try gargling with apple cider vinegar, or hydrogen peroxide.
fresh cayenne is the universal cure all, and i recommend it for just about everything.