To determine the safety, effectiveness, and toxicity of topical (local) trifluridine in treating mucocutaneous (at the nasal, oral, vaginal, and anal openings) Herpes simplex virus ( HSV ) disease that has shown resistance to acyclovir in HIV-infected patients. HSV infection in patients with AIDS is often associated with skin sores and frequent recurrences. Treatment with the drug acyclovir results in healing for most patients, but repeated treatment sometimes results in resistance of the virus to acyclovir. Thus, when this happens, other treatments need to be used. Trifluridine is an antiviral drug that is used for the treatment of Herpes infections that occur in the eye. This study attempts to determine if trifluridine is useful for treating HSV sores that have not healed after treatment with acyclovir.