I hope you feel better.

Pain and about anything else can cause a flare up for me.

Can't you get to the ingrown nail to get it out of the skin or cut it? It will come back if you cut it but you may have an infection by the time of the doctor's appointment.

If you didn't have an infection or RSD the best course of action is sometimes using a product like OutGrow which is over the counter at the drug store. I don't think you're supposed to use this if the skin is broken or it's infected.