Error in master's thesis, I do not know what to do
Revoking an earned degree is exceedingly rare and would probably be appropriate only for serious and intentional errors such as fraud. I think you can rest easy on that. 

Talk to your advisor and lay it all out. It is better that you find and reveal the errors than if someone else does. Going forward you can still publish, but it will need to be based on correct data, analysis, and interpretations. 

It is common in research for errors to appear in old work. It is certainly not a unique occurrence. Attempting to conceal it would be the worst path of all.