Since Peatie is "eating VERY well, running, playing, no signs of not feeling well at all, except the swelling", I would think it could wait til you see your regular vet on Monday.
Had he been in any distress I'd say, go now.
An E-vet will cost the same now, tonight or Sunday so if things change, go then.
We all know how costly E-vet service can be. Never feel bad because you decide to wait. You are the one right beside Peatie and can best judge if something is off enough to be a true emergency.