Unfortunately for most types of skin masses, you cannot treat them at home. You can however, monitor them for changes which will provide useful information to your veterinarian when they assess the mass.
If you notice any changes to a mass on your dog’s skin or identify a new mass, it is a good idea to book an appointment with your veterinarian to have the mass examined.
They will likely start with a visual exam of the mass—noting size, color, how firm it is, whether it is located solely in the skin or if it extends to deeper tissue like the connective tissue layers. All this information can give hints as to the type of mass, but is not enough for a conclusive diagnosis.