Melanoma is skin cancer of the pigmented cells found in a nevus or mole. Melanoma is thought to be due to genetics and/or excessive sun exposure. Melanoma diagnosis is made through a surgical biopsy or excision of the skin that is done by your dermatologist.
The prognosis and treatment of melanoma depends on the type of melanoma, depth of the lesion, and whether has spread to the lymph nodes or other organs. Unfortunately, melanoma is a type of skin cancer that can be invasive and life threatening. However, when caught early, as it is in the majority of cases, surgical excision can be curative. If it has spread, we are fortunate to have some advances in treatment of metastatic melanoma in the past few years with the advent of new chemotherapeutic medications.
It is important to have close follow up and regular skin exams with your dermatologist after the diagnosis of melanoma. The recommendations include a full body check every 3 months for 2 years, every 6 months for 5 years and every year thereafter. In addition, doing self body exams fully naked in front of a full-length mirror once a month may be helpful in spotting a mole that is changing earlier even than your visit. Enlisting a spouse, parent or partner also has been shown to increase the chance that a melanoma will be spotted at an early time.
It is extremely important if you have had a melanoma to protect yourself from the sun. If you don't, it would be akin to smoking after a diagnosis of lung cancer. There are many tips on sun protection under the dysplastic nevus section, please refer to this. It isn't true that all the damage was done and therefore it doesn't matter if you do more. Cancer is a step-wise process and sometimes it is just that one more exposure that pushes you over the edge. Finally, because it can be hereditary, please inform all of your relatives you have had it (including cousins) and encourage them to have their skin checked by a dermatologist.