I started out making my Homemade Mystique Halloween Costume by ordering a blue body suit online. When it came in, I set to work making myself scaly by covering the suit darker blue puffy paint. This took a few days, as I had to do parts with the suit on and then do the complete front while it was off and then the complete back while it was off, giving it drying time between sessions.
I bought red hair coloring spray to make my hair work, and I applied that over GENEROUS amounts of cheap hair gel. I used cheap acrylic paint to make the rest of my body blue and more of the puffy paint on my face, hands, and feet to complete the look. I painted my feet and wore a pair of blue flip flops.
Since I needed some sort of purse to carry around my things, I cut out two matching cardboard gun shapes, spray painted them black, and taped them to either side of my black clutch. The result was so-so but more believable than Mystique carrying a clutch!
The paints were not made for body use, but they worked very well for the price, and the only issues I had were with areas where I crease (like my neck) and areas where the suit met the paint (like my chest) peeling. I had to reapply multiple times during the night.