Answer:
Here are a few options you can say back to someone who said "Good feeling better now":
"I'm glad to hear that! Take care of yourself."
"That's great news! Let me know if there's anything I can do to help."
"I'm so relieved to hear that! How are you feeling now?"
"I'm happy to hear you're feeling better. Take it easy and rest up."
"Good to know, take care and don't push yourself too hard."