I found a lot of dialogue choices requiring high Perception and I started the game with just 10 plus 1 for being an elf. With a magical helm and tower rest bonus I can temporarily boost it to 13, but is it possible to raise it permanently?
You could do that with cheats - either with console command
AttributeScore player <attribute> <amount> or there are CheatEngine tables that allow you to do that without loosing Steam achievements.
Custom enchanting will allow you to increase whichever stat you need with your favourite equipment options.
Drugs can do a temporary increase to get through the conversations you want.
That said I know of no permanent way within the game to increase it, neither by level-up nor quest reward.