Hey Rachel!
Drink plenty of water, at least a few days before your session. It will help a lot. (Make sure you pee before you go though!)
An OTC or prescription NSAID may help. I have naproxen (aleve) and ibuprofen in prescription only strength that I keep for emergencies (gout attacks) but I've been using it prior to the session. OTC works as well. However BE VERY CAREFUL as they can cause clotting and liver damage. Don't overdose for any reason. Follow the label and/or your physician's directions.
You can also opt for a skin numbing cream containing lidocaine instead of or in addition to the oral painkiller. I've found that helps immensely. Apply like a half hour to an hour before.
Make sure you give accurate feedback to your electrologist. This is critical. Especially if the hairs are plucking and not easily sliding out. He or she should know if the settings are correct and hairs that are plucking are simply wasting your time, pain and money.
Work near your pain threshold. No pain, no gain and you want an effective kill of the follicles. That means it more or less must hurt, unfortunately.
Some areas hurt more than others. Upper lip and right below the lip are really bad. One side of your face may hurt more than the other.
After treatment:
Your face may be red and swollen. Be prepared if you have to go back to work for example.
No makeup, creams, or other stuff on your face for 2 days minimum after the treatment. Witch Hazel and maybe bacitracin (topical antibiotic) or similar helps.
Don't pick scabs. Don't exfoliate scabs either. Let them flake off on their own. A good electrologist won't leave many anyway but sometimes they are unavoidable.
Shave using a CLEAN razor. A dirty one can get you infected. Buy a pack of disposables and use a new one after each treatment.
This is all based on my experiences, but your mileage may vary. Also remember it's a marathon, not a sprint. It may take up to 3 years to clear a full beard unless you're going to E3K or similar who do full clearance in marathon sessions. I'm taking a break from electrolysis to do laser to clear most of my hair and I'll resume after laser can't do any more.
Good luck!