worried about potential melanoma/skin cancer

Hello, I’ve recently noticed my freckles have gotten a lot darker and at least two are rough around the edges and ridged. I’m aware that exposure to UV can cause this, however about a month a go I started using sun beds to help clear my eczema as it was the only thing that helped. I wasn’t going on regularly and solely on the basis to try and keep my skin from flaring up as nothing else seemed to work. I am now worried as I am only 18.