###Human: What causes cold sores and rashes on the lining of my lips during periods? ###Assistant: Hello. The allergic rashes if they are occurring specifically during menses and the only line the vaginal lips then the cause is unlikely to be menses per se but rather the material of the sanitary pads that you are using from day one. If you have changed the brand of the sanitary pad lately then please revert back to the earlier one and in the meantime, you may apply ointment Candid-B locally over the labia minora and majora over the rashes thrice a day and try to keep the local area dry as much as possible. Also change pads every 3 to 4 hours, again depending on the bleeding. If possible please share the picture of the lesions to rule out allergy from herpetic eruptions.