Go to any mirror and put your hand against the glass. Don’t worry, nothing will grab you. Wait. Sometimes it takes half a day, sometimes it takes a moment. But you’ll yank your hand away when you feel it.
Worms or centipedes, who knows? All pressed in tight like there’s no more room on that side, wriggling against your skin. When you pull back, the glass is the same and you’ll be unharmed.
But now you know it’s there.