A mouthwash of medium-hot water with a teaspoonful of salt will help to reduce gum soreness and inflammation (check that it is not too hot before using it). Swish the salt water around the tooth, trying to get into the areas your toothbrush cannot reach. Do this several times a day.
An antibacterial mouthwash containing chlorhexidine can also reduce the inflammation. Pain-relieving tablets such as paracetamol or ibuprofen can also be useful in the short term, but talk to your dental team if the pain continues. The tablets should always be swallowed and not placed on the area.