If her friends do similar then, unfortunately, she is more likely to listen to them than anyone else and won't want to not join in.
Make up application has a knack and it can take a while to get right, especially a more natural look. What kind of makeup is she using? Cheap stuff may be making the situation worse.
I never got the orange look though some seem to love it (similar with the tanning obsession). I tend to avoid make up counters as they seem intent on making you look like you have a tonne of make up on. Trouble is, fads are usually obvious with hindsight, I remember well the fluorescent days, shell suits, dodgy perms....
Does she have any skin problems? Something she could be trying to cover up that may be way more obvious to her than anyone else, especially as she is at a very self conscious age, spots, large pores, redness etc... That could be a reason for plastering it on.
Some girls almost seem to see it as a mask. I know someone who used a lot of make up and would only take her make up off right before she reapplied it, said her partner had never seen her with no make up on, slept with it and everything.