When you want to tell someone who is sick to get better, the phrase you want to use is
The point here is that you say this as a farewell to someone who is not in their well-being, or temporary injured at the point.
Some people confuse this with phrases like
お気をつけて (okiwotsukete) Take care, have a safe trip
おやすみなさい(Oyasumi nasai) good night.
Please make sure to get these right!