It depends. The long term effects of having melanoma depend on how deep the cancer is at diagnosis and whether it has spread beyond the skin. For very thin (in situ) lesions, there is very little impact after the lesion is treated. On the other end of the spectrum, thicker melanomas that my have spread can be fatal. If you have been diagnosed with melanoma, discuss your prognosis with your dermatologist.
Depends on the stage. Early stage melanoma is highly treatable and the long term effects include having a scar from the wide local resection. Later stage melanoma involves removal of the lymph nodes which can lead to lymphedema. In addition the average 5 year overall survival for stage 4 melanoma is only 15%.
Depends. This depends entirely on the breslow thickness, or depth, of the melanoma. The deeper the melanoma, the more serious the possible long term consequences. Discuss this in detail with your doctor with the pathology report in front of him or her. Good luck!