。
She sometimes has her mother cut her hair.
Literal
She [topic-は] sometimes mother [from-に] hair [object-を] cutting receive.
~てもらう ('have someone do for me, receive someone's doing') is one of Japanese's giving/receiving auxiliaries (授受表現). The に marks the source/agent — the mother here is the cutter. The construction reframes the action from the receiver's perspective: instead of '母が髪をカットする' ('Mom cuts her hair'), 母にカットしてもらう says 'she has Mom cut her hair' / 'she gets a haircut from Mom.' カット is a loanword used specifically for cutting hair (and stylized cuts in fabric/film); the everyday verb for ordinary cutting is 切る. The split vocabulary — カット for stylized hair-cutting, 切る for general cutting — is a small but distinctive feature.