。
Get a friend to help you.
Literal
Friend [source-に] help-and [receive favor-もらいなさい].
友人 ('friend') is the slightly more formal counterpart of the everyday 友達 — both mean the same thing, but 友人 leans toward written or polished speech. The construction 友人に助けてもらいなさい uses the benefactive ~てもらう ('receive the favor of being helped') with the soft imperative ~なさい — the structure literally means 'have a friend do the helping for you.'