Permanent fix......
Get a tube of FLEXIBLE 5200 (reiterate *FLEXIBLE* 5200); dab a little on the patch (try to use the SAME material as the sail), let cure! Flexible 5200 is usually available at most sailmakers supply sources. Sail repair tape isnt good for anything but a quick spinnaker repair (and for use in a non stress area as it isnt strong enough nor has the adhesion to hold panels toegether, etc. Since I discovered flexible 5200 I dont even carry my sewing machine along on long voyages anymore, just a few tubes of flex 5200 and a few scraps of sail material plus a roll of 2" sail tape.