A custom race doesn't give you a custom face. It gives you a custom face blueprint that is further modified by all of the facegen stuff when you actually apply it to your NPC or player preset. If the custom race version is pretty close to what you want, then you'll probably want to adjust all of the sliders in both the Geometry and the Texture section of the NPC pretty close to the middle (zero) for each slider. There are some shading and tinting effects that always get applied whether you want them or not, which is a royal pain in the backside sometimes. Unfortunately, there's no way to disable them that I know of.
Since the GECK is really an evil Vault-Tek experiment designed to test modder's frustration levels, one of the annoying things that it does is any time you even click on a race to view it, it marks that race as changed. Your mod will therefore not only create your custom race, but it will also overwrite any other mod's changes to the Caucasian, Asian, Asian Child, and Ghoul races (and maybe others - that's all I can see that are flagged as changed in your screen shot). If you don't want your mod to change these other races, when you start up the GECK, select your mod and press Details. Then select the races other than your custom race one by one, and press Delete. That will flag those changes so that they don't get loaded when you next load up the GECK. Now load your mod up as usual and save it. That will get rid of the extra races in your mod that you probably didn't want to modify.
Alternately, you can use FNVEdit to remove the extra race records. It's a bit less clicking and fiddling to do it in the GECK, but either way works.