So the real question here is HOW is this money invested? Is it in a stock market fund? If so, you probably lost some money — even though the market has rebounded.
I’m thinking this is inside a retirement-type account, and tax-sheltered. If that’s the case, then taking the money out would generate taxes. But there are certainly some other investment alternatives INSIDE the plan. Call them and ask about the alternative investments that you can switch to inside the plan without tax issues.
This decision depends on your own risk tolerance and how much other exposure you have to the stock market. (You should have some stocks, despite the risk, because you have a 20-year time horizon!). See if they can explain the alternatives for you — perhaps an equity/income fund that invests more conservatively. Or perhaps if this is you only stock market exposure, but not your only retirement money, you should leave it and see what happens over the next 10 years!