Yes, and no. All you really did was give your bro spiked buck teeth, a third eye, and changed his skin tone. As for yourself, you changed the skin tone and the color of your eyes. Hardly scary. This might seem counter intuitive, but rather than give your brother giant spiked teeth, try giving him much smaller spiked teeth, and lots of them. You could remove his nose, and create the effect of a rotting corpse, or just someone who's been in a terrible accident or suffered from a disease. How would the nose look? I'm sure you can find some disturbing pictures on google of what that looks like. If you're not to doing that, just find a picture of a skull and copy what the region where the nose looks like without the cartilage.
Eyes are a bit harder. Red eyes aren't eerie. Ever. Black in black eyes? Much better.
Like I said, try to find some "scary pictures" and copy the scary elements from those pictures. After mimicking them a bit, you'll find it much easier to create something from your imagination since you now understand the concept.