What complications stem from perforating the sinus floor when drilling to place an implant?

My best friend had dental surgery yesterday to get an implant. The tooth is the one behind the eye tooth. When drilling into the bone to make a place for the screw, the dentist perforated the sinus cavity. The patient heard/felt a “pop” and the dentist confirmed that the drill broke through. He placed the screw along with a bone graft around the screw. Patient was told to guard against exposure to illness and be careful not to blow nose hard or suck through a straw. We are wondering if the perforation is an issue or will it heal up and be like it was never perforated. Also any special care advice would be appreciated. Thanks so much.