If it is a little uncomfortable its fine, you can even do several things to stretch them out and make room.
one example: put the liners in the dryer on high for like 20 minutes, in the meantime make some fat socks. I cut the front 3 inches off like 6 old socks, 3 on each foot and then put a really tight thin bike sock over those, followed by my snowboard sock. Put the liner on, put it in the boot, TIE EVERYTHING COMPLETELY and wear it for as long as you can stand it or until the heat is gone. For me this was extremely painful but 2-3 sesssion of 10-20 minutes each made a huge difference and now they fit great.
If they are super squished all over they are too small.
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