Hi! Welcome to Healthcaremagic. I read your query. White cluster at the corner of mouth can be due to various reasons such as accidental biting, fordyce spots due to sebaceous glands, oral herpes, allergic reaction, or other severe conditions. Since you mentioned that there are no symptoms associated. Even then I suggest you to once visit a dentist and get them checked. If they change shape, size or texture, go for biopsy. In case of history of any medication causing allergy, contact your physician before stoping or changing drug. Herpes infection takes usually 3-4 weeks for complete healing. Hope the answer helps you. Thank you!