Dont' be offended by the 4- it is more of a 4.8 your painting is right on the cusp of a major breakthrough as you have the grasp of some concepts but are lacking in others- my advice is to pick one area to work on- maybe washes cause those are easy and go a long way- and read the articles. The conversion is pretty good- at least a 6
I'm not exactly sure if you want a comment on the conversion or the painting. So I'll give both. I think the mini is funny. The hand is well done.
I terms of painting you need to thin your metallics down. You could probably stand to thin everything down, as it will help with shading. It takes a lot longer to paint a single mini, but the results are nice.
Teeth and bones should never be white. That's my opinion anyway. If you are using Citadel paints I'd go with Elf Flesh for the teeth and nails, then high light it with Palid Flesh. The skull needs a lot more shading and I would use Bleached Bone.
You actually have some decent shading on the red skin. But it looks like everything else has a single coat over a black base.
For the hair I'd recommend painting it yellow then washing it with a very thinned down black or even a brown.
And, as always, pay more attention to your base. Some sand or flock would make this appear much better.
That's probably more advice than you wanted, but you asked.