Leave/let well enough alone informal verb phrase
Try to avoid to change something because doing something else could make things worse
I could do it again, but I let well enough alone.
I should have left well enough alone, but I didn't. As a result, my project was damaged by myself.
The verb "leave/let" should be conjugated according to its tense.
The story of this phrase is derived from ancient Greek times, specifically Aesop's fable. It's about a fox who refused a hedgehog's offer to take out its ticks lest, by removing those that are full, other hungry ones will replace them. It was first recorded in 1827.
hurt someone or yourself
If you try to carry that suitcase, you’ll do yourself a mischief.