I'm not sure if I experience the same thing, but it sounds similar.

It sometimes happens with peoples faces, more often with my laptop screen when I've been staring at it for a while. It is impossible to put into words... sort of like my sense of size becomes meaningless. Depth perception vanishes. Sometimes things seem very small, or very large, but that is not quite it. It is more like my brain doesn't know how to parse anything related to absolute size.

Sometimes when I'm trying to fall asleep, I'll experience it with very high intensity. Normally when I think of an object, it is in one of two ways. Either I'm modeling it in my head, in which case it seems roughly head-sized and located (where else) in my head. Alternatively I superimpose it on the environment, and I can roughly envision it at appropriate scale. So whatever part of my brain that is responsible for these tasks seemingly deactivates. It's really interesting in an abstract way, but its accompanied by mild nausea and vertigo.