This could be better. Take the advice from other comments below and you are golden.

Not bad, but as stated below people have done this befor and done it better. That being you have great potential, so long as you follow the advice below. I wish you luck with your next war paint.

I like the idea, although other people have already done it and done it better, although for your first warpaint its actually alright, and I can tell you'll get better as you become more experienced, so keep up the good work!

Not bad for a first warpaint. However, I first of all advise you to ensure that the texture is seamless on all sides. If your art program has an offset filter/tool, it is useful in making patterns. Additionally, I suggest not using solid black for the primary as well as refrain from making large striped patterns on secondary and tertiary textures, since they do not scale well when rendered in-game. If you must however, make the stripes a lot smaller.

make some good warpaints before you critique them

Nice nuclear pattern warpaints, I enjoy seeing normal and average going warpaints, hope to see more like this