Sure you have to see the result of the evaluation. Otherwise it even doesn’t make sense. If there are some areas in your work that have to be improved, you must be aware of it, right?

As for being underestimated, usually we all tend to feel that we are better than other see us, especially when it comes to the evaluation at work. So this is a bit subjective and you cannot really do anything about it.

But if you completely disagree with the result, you have 3 options: leave it as it is; speak to your manager (be careful here, the consequences might be crucial); or just start looking for another job...