Some cars (most of them) are totally immune to any harmful effects of overfilling. Their owners do it at every fill-up and have done so for years. A few cars suffer. Dunno about the Forester.
You will find out when you next fill your tank. If the procedure is normal, no damage has been done. Forget about it. If you can only squeeze in a bit at a time, the nozzle clicking off, then a problem has occurred. As for immediate remedial care, there isn’t any. What happened has already happened. Drive normally without worries. Most likely nothing untoward has occurred.