Can my iPhone be hacked by responding to an iMessage?

Tonight I received an iMessage that seemed legitimate, though the sender's name did not appear, only a phone number. When I responded to the iMessage I received the response "Sorry my friend i gotchu." I didn't click on any links - there were no links in the iMessage.

Now I fear that my iPhone may have been hacked. My iPhone 7 was running iOS 15.1. I just noticed that iOS 15.2 is available, but automatic update hasn't yet installed it.

As a precaution, I've been changing passwords tonight using my MacBook. The passwords are stored in iCloud. A few minutes after I changed my Apple ID password a popup appeared on my MacBook and my iPhone, saying "Your Apple ID and password are now being used for FaceTime on a new iPhone. If you recently signed into [my wife's iPhone 12] you can ignore this notification." My wife's iPhone is on the same Apple ID as mine.

Should I be worried about a hack of my iPhone? If so, what should I do?