If you don't have meds on hand you can SLOWLY(1-2 degrees every 45-60 mins) up the temp to 86 degrees. You can also add salt at 1 tablespoon per 5 gallons.
This is known as the heat and salt method. It basically speeds up the life cycle.
That being said, it's going to look worse before it looks better. Id be doing water changes and vacuuming every day.
If you see no change after a week of treatment I'd bust out the meds.
Caleb