My daughter has swelling and redness over, what I think, isher wisdom tooth trying to come in. Her jaw is sore. It's a saturday night. What do I do?

Swollen gum. If it gets worse or she has a fever call your doctor and dentist. They can help you make sure it's not an abcess or infection.
Teething. She's teething, just like she did when she was a baby. And it always seems to happen on a weekend. Irrigate the area (bulb syringe from drug store) with warm salt water. Dab on Orabase-B w a Q-tip. Take Ibuprofen/Advil/Motrin exactly as per package directions. Call wisdom tooth specialist, an Oral Surgeon. You'll get their answering service. Make arrangements to be seen ASAP.
Hot salt water. Use an "ear syringe" available in a drug store, pull salt water, teaspoonful in a glass of hot water . Put tip of syringe at flap of gum and squeeze hard. Then call your dentist.
Ice chips. I would try a dental hotline in area if you have one. If not, rub some ice chips over the area and tylenol (acetaminophen) or some anti-inflammatory if can take it and if you cannot get into a dentist soon.