See a dermatologist for the existing tumors; they need to be examined and determination made of urgency for treatment. Ask for a whole body examination - ask for questionable looking moles to be marked with an indelible ink marker.
Take photographs at home. Use common points of reference (anatomical) and measurements to make sure you can locate these moles/growths/hyperpigmented areas again. Have the dermatologist prioritize them for you, for treatment.
Buy the large size mole treatment
(cancerx.org or
http://curezone.com/forums/f.asp?f=651 Black Salve forum)
..and use Indian Black Mud salve (typically contains two forms of bloodroot plus another two herbs that induce tissue repair). This will effectively remove the carcinomas without resort to surgical intervention, drug use etc.
Treat all of the marked areas, bit by bit. Do NOT treat them all at once. At most treat 2 at a time. This serial treatment will probably take a year or more to get all of the culprits removed.
Read these two sites so you know what to expect. Read the forums to help you understand the process and followup treated site care to encourage fast healing, reduce secondary infection risk and reduce scarring. In most cases, done properly, scarring is very minimal.
This salve treats only the surface altered growths. Some moles with very deep roots may need more than one treatment.
For marked sites that need to be treated on the back and on difficult locations for reach for self treatment, you will need to educate the person who will be helping you with salve application, observation of treatment progress and post tumor/mole removal care.
This treatment is fairly widely known, but rarely discussed within these forums.
I suggest all forum members who have had repeat sunburn and excessive sun exposure events to consider this approach to self-treatment to manage risk for skin cancers. A physician must be included in this treatment process, if tumors are present, because of the possibility of tumor metastasis (spread of tumor cells to other locations in the body).