Need some support or ideas what could be happening? Swelling of whisker area

On Saturday 1/18 we noticed that we accidentally booped our boy’s nose and he yipped. Nothing wrong with him that we could see with his nose, teeth, or snout.

Then the next couple days (we live in Houston) we went through a winter snow - atypical for us. I noticed that if we touched his nose with light pressure, he was fine, but anytime he put moderate pressure on his nose, he’d cry out in pain. Again, no issues that we could see with his nose, teeth, or snout. Wednesday 1/22 is the second picture.

I texted his vet and planned to get him in to see his preferred vet once the ice and snow melted over and his vet was in the office (Monday 1/27).

Then yesterday 1/23, when I came home from work, his left whisker area was NOTICEABLY swollen (first picture). And I can audibly hear his exhales be a bit more nasally then normal.

Cue my freak out. I text our vet and say IDC if it’s not his preferred vet, I need my boy to be seen. He’s there now, and they’re doing a work up. I just don’t know what it could be? What could be causing him discomfort on Saturday and then swell up 5 days later? This is my soul baby and I don’t know what I’d do without him.

Keep in mind, all through this morning, his temperament has not changed at all, he was eating fine, peeing, pooping normally, drinking, playing (just being more gentle when using his snout), and tail wagging. That has been my only saving grace and solace in this whole thing.