Hi.. Thanks for the query.. The symptoms of mouth sores along with bloating and full feeling can be due to side effect of the long term intake of medication as Enbrel is used to treat auto-immune disorders and can have a number of side effects. Red bumps all over can be due to allergy to the injection that you have taken.. Consult your Physician or an Allergist and get evaluated.. You can be advised anti allergic medications to relieve the allergy symptoms.. Topical application of calamine lotion and Caladryl lotion can relieve.. For mouth sores and itchiness inside mouth you can start gargling with numbing mouthwash like Lignocaine to relieve pain and itching.. You should take Vitamin B complex and lysine supplements.. Gargling with a solution of milk of magnesia and benadryl solution can help.. Do cool water rinses and sucking ice pops can help.. Hope your query is resolved.. Regards.