What is the prognosis for stage 4 melanoma?

I'm 44 and had a mole removed in 2003 and it came back as malignant melanoma. I had surgery on the site a large piece of my back was removed along with the lymph nodes in my left armpit. After many follow-ups and biopsies I was cleared. Last August I went to the emergency room thinking my appendix burst. I felt a lump in my lower right side of my stomach but didn't think anything about it. I had a CT scan and the doctor told me there was a very large mass. The surgeon didn't want to remove it until he did a biopsy. Well the news came back as malignant melanoma. I had asked the doctor if it could be related to the cancer I had in 2003 and he said very unlikely, but in fact it was. I had surgery and the mass was connected to my bowel, bladder, lower intestine and right ovary. It was the size of a large melon! The site became infected and I left the hospital with a open area from the top of my belly button to my vagina. I had to pack it twice a day wet to dry bandaging and then was told it spread from the original site and that there isn't anything to treat since they removed the tumor and because chemo doesn't work for skin cancer. I have read up about this and have a positive attitude but isn't there something to be done to keep it from spreading? The oncologist said it was to far gone and to expect more tumors to grow and they will treat them as they come. I have a lot of pain now in my joints and still in the area where it was removed. I also have a very large open scar that was suppose to be closed or fixed once it healed. I am sorry if I rambled on and didn't keep to a short question. This is the first time I have asked about myself and kind of let it all out. I just want to to know what is out there for stage 4 melanoma? My doctor did say I was lucky it didn't spread to my brain - that is the first place it spreads when it comes back.