Of course I had to google it, and I seem to have missed whatever's so disgusting about it (guessing an insect-infested wound or something based on reactions here).
"Trypophobia is a claimed pathological fear of holes, particularly irregular patterns of holes. ... Shapes that elicit a reaction were said to include clustered holes in innocuous contexts such as fruit and bubbles, and in contexts associated with danger, such as holes made by insects and holes in wounds and diseased tissue."
I wish I hadn't googled that. It may be time to license photoshop on a certain kind of ethical requirement to not create certain images. Those images are so disgusting, my teeth hurt.