Good timeframe for seeing a doctor about potential skin cancer?

I worked for a dermatologist for 5 years and saw many different types of skin cancer. Warning signs are a sore that will not heal, redness, getting larger and even a mole that has changes size shape or color. Your friend should see a dermatologist asap because some skin cancer is more agressive then others. BCC basal cell carcinoma is a slow growing skin cancer, some people have it for years and it is not that agressive, but still needs treatment or it can turn into a SCC which is a squamous cell carcinoma. This is a tissue damaging cancer and if left un treated for long amounts of time could result in very extensive deep tissue surgery for removal, or even a surgery called MOHS which is a micrographic surgery for skin cancers that are very large and require stage removal. IF it is a mole that has change beware of Malignant Melanoma which is potentially deady if not treated in a timely manor. Your friend needs to see a doctor and have a biopsy done, they will send it in for testing and call her with the actual lab results. Hope this helps.