Upper Ball Joint came out while driving

They are not press fit ! They screw in with special sockets. The hex shape should be a clue. Well its not hex but a special shape like oil senders and such.
I see you joined here very recently so we'll forgive your not asking / knowing. Never expect correct answers these sort of questions from the kid at the parts counter.
Your options are replace the parts or weld them. Tack welds on the top aren't enough. Weld the underside. Good luuck