It depends on exactly what you mean. "Take some time for yourself." This means take some time to take care of or to pamper yourself, to focus on yourself instead of other people or things. "Spend some time alone." This means to take some time to be alone, by one's self, not with others. "Take some time off." This means to be away from work.

It's perfectly correct. I think the context makes it clear. Or...?

As they say above, the sentence is a bit vague.

"Spend some time with yourself". Would make more sense.

Spend some time for yourself. Everyone needs to pamper himself once in a while... that is the context.