Thank you all most sincerely!
@ GrandpaBob: Good point about the shadow, now that you mentioned it I can't unsee the unnaturally sharp black line either! Fortunately that's easy to fix, thanks for notifying that.
@ SquarePeg: For sculpting I always use kneadatite aka Green Stuff. With a little bit of practice, water and a sculpting tool you have basically endless opportunities for modifying your models.
The white parts are usually the hardest parts, since painting clean white can be a real pain in the ass sometimes. I normally start by painting the areas light grey and then start painting on multiple layers of watered down white. A very heavily watered down black (or black wash, if you use Citadel paints) sometimes works wonders, too. The key thing here is to paint the white in multiple thin layers - one or two thick layers won't work and can look horrible if rushed. On the other hand, the white color can't be too watered down; if the paint drips from the tip of brush, it's too wet. After a couple of attempts I bet you'll do fine.
I've been busy with my Real Life™ lately since I moved to my own apartment just a couple of days ago. I'll have some eldritch monsters painted within this month though, unless I get distracted too much with other projects.