make it up to (one)
1. To do something to make amends to one for a transgression against them or some disappointment. I'm so sorry for missing your recital. I promise that I'll make it up to you somehow. I know you're disappointed about missing the movie, but I'll make it up to you.
2. To perform a favor for one as a means of repaying them for a favor they performed in the past. I don't know how I'll ever make it up to you for all the kindness and support you gave me after my father passed away.
make something up to someone
to make amends to someone. I'm so sorry. I will do what I can to make it up to you. I will make it up to them. Don't worry.
make up to
Make ingratiating or fawning overtures to, flirt with, as in She was always making up to the boss's assistant. This usage was first recorded in 1781.