Raising the temp like you did and gently swirling the yeast back up into suspension seems to work for a lot of people. It never worked for me, though.
Next time aerate more than you normally do and see if you notice any difference.
Primary/Secondary: #109 Rye, #110 APA
Kegged: #106 American Wheat, #107 IPA, #108 Nut Brown
Planned: Red IPA, American Brown