I have the same thing and it's from Neuropathy which was caused by my MS. It's my right foot, it always looks swollen except for when I'm lying down. Once I get up and put my foot on the floor it turns red and looks swollen. Look into electric stimulation for Neuropathy. I just got a device called an H-Wave that I hook to my legs and feet to help with the Neuropathy pain. Works pretty well.

If you are experiencing swelling in one leg only go to emergency so they can examine. Please don’t wait too long.

The problem is that a blood clot can kill someone, only a doctor can remove it

I agree with UMN. Get to a doctor quickly. I have been wearing special hose for years and they reduced the swelling significantly. My legs feel much better too.

I suggest you seeing a doctor urgently because it can be a blood clots
It can be the hospital it's open today
https://unmhealth.org/?ved=2ahukewifm77y6smhaxx...

UNM Health System | Albuquerque, New Mexico

https://unmhealth.org/?ved=2ahukewifm77y6smhaxxcdqqehymtbyiqgu96bagueba