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.

道に迷った時に、周りの人に助けを求めるための丁寧な表現です。