道(みち)に迷(まよ)ってしまったのですが、手伝(てつだ)ってくれますか。

This is a crucial phrase for asking for help when you are lost and need directions. It's polite and directly expresses your situation and your need for assistance from someone nearby, which is very helpful.

道(みち)に迷(まよ)った時(とき)に、周(まわ)りの人(ひと)に助(たす)けを求(もと)めるための丁寧(ていねい)な表現(ひょうげん)です。