The phrase "to recover lost ground" means to regain something that was previously lost or declined, typically in the context of achieving progress or improving a situation. Full definition
The younger you are, the less of a concern this should be, as in the long term, investments pretty much always recover lost ground. (money.stackexchange.com)
Bitcoin quickly recovered lost ground, and all digital currencies are making a comeback, but we're far from the highs registered earlier this week. (bgr.com)
Since then, P&G has simply recovered lost ground; its current stock price is hovering right where it stood two - and - a-half years ago, at around $ 93. (fortune.com)