下手へたをすると

expression

if things go wrong; if one is careless; at worst

Fixed adverbial expression used to warn about a possible negative outcome. Often implies that a small mistake or bad luck could lead to a serious result. Similar in tone to 'if you're not careful' or 'in the worst case'.

• 下手へたをすると大おおけがをするかもしれない。

  If you're not careful, you could get seriously injured.

• この計けい画かくは、下手へたをすると大だい失しっ敗ぱいに終おわる。

  If things go wrong, this plan could end in a huge failure.