Baby rubbing face in sleep ?

My son is 20 weeks old. For bedtime I usually do the side lying breastfeeding position and let him fall asleep like that because I found it’s the best way to get him to sleep 10-12 hrs at night. Usually I’ll let him lay next to me sleeping for about 1-3 hours (I’m always awake on my phone) and then I’ll gently pick him up and put him on my chest to burp him while he sleeps and then swaddle and put him in his bed. This has been working for the last 8 weeks no problem. His arms are usually out and that’s no problem but for the past 2 nights he keeps fidgeting around and rubbing at his face in his sleep and he ends up waking himself up. I’m not sure why he’s doing this? I’ll swaddle him and lay him down and he just starts turning his head left and right multiple times before stopping. Or he’ll fight to get his arms out and usually when he gets his arms out it’s no problem but now he’s rubbing his face.

I haven’t really changed anything in my diet besides the fact I ate crawfish couple nights ago. Could he be having an allergic reaction? Or just the 4month sleep regression? Teething maybe? He has a bunch of hair so I hold it off his face while he sleeps in case it’s ticking him but that doesn’t work he still tries to rub at him face. I ended up putting mittens on him but he starts sucking them while sleeping leaving then soaking

Not sure the group so I’ll just do this one lol