Hi.. Thanks for the query... I have gone through your query and can understand your concerns.. As per your complain your symptoms of burning and chapped lips along with burning inside mouth are all pointing towards an oral condition known as Burning Mouth Syndrome.. Burning tongue/mouth syndrome is a condition in which there is burning sensation inside mouth and can also be associated with a scalded feeling and can also experience numbing sensation.. As you are taking Gabapantin then there is a possibility that it is the culprit as Gabapantin can cause dry mouth that inturn can cause burning sensation and inflammation inside mouth... Other common causes that are seen to cause similar symptoms are nutritional deficiency of iron and vitamin B12, dry mouth or xerostomia, stress, acid reflux, side effects of medicines etc.. I would suggest you to consult an Oral Physician and get evaluated and a thorough clinical examination and investigations like blood tests can be advised.. Treatment of underlying cause will resolve the symptoms.. As of now to get relieved you can start gargling with a numbing mouthwash containing Lignocaine.. Take anti inflammatory painkiller like Ibuprofen.. Avoid spicy foods and take a soft bland diet.. Suck ice pops.. Hope this information helps.. Thanks and regards. Dr.Honey Nandwani Arora.