We understand the pain of cold sores and fever blisters inside and out. Youve probably tried many medicines to help with the healing and discomfort. Hyland's Cold Sores / Fever Blisters relieves the painful symptoms of unsightly cold sores.* They also work on cracked lips, as well as canker and mouth sores made worse by acidic foods. Theyre safe for adults and children and can be used in conjunction with other medications.