You must let it dry out thoroughly first however long it takes; it could be weeks if it’s really bad & ideally should be tested with a damp meter if you can get hold of one. If you try to overboard while it’s still damp the adhesive won’t stick, you’ll get mould & musty smells. A heater will certainly help but leave the bathroom window open & the door shut, if you don’t the moisture will just condense on a cool surface somewhere else in the property. A dehumidifier should also be used if you have one as this also extracts moisture from the air, speeding up the process.