Volume loss eyelids (strange phenomenon) - what's causing this? (Photos)

Hi, it feels like my eyelids have drastically changed in the last 5 months. I’ve developed a double eyelid on one side and appear to be developing a double eyelid on the other. Looking back on pics from a year ago I can see slight volume loss but not this drastic. The youthful pic is from 2.5 years ago. What’s causing this? For three years I’ve been doing facial exercises and using tretinoin. Weirdly, before my period my “youthful eyelids” return and I have these lids from 2.5 years ago. Thanks