Normally you would use ice or cold to reduce swelling, but obviously that won't work for a reptile. Then my little runt got her neck caught on the tub edge there was some swelling as well, the vet said there's nothing they can do about it (unless it's the emergency, airway-opening kind of intervention). It took a few days to go down and there was some bruising that appeared around 12-14 hours later (so don't be shocked if you see some of that appearing on your girl in a few hours) which took a bit longer to clear, but as long as her airway hasn't been compromised she should be ok. Personally I would give her a week or two off food until it heals up, as her neck is probably quite tender.