Brian Austin Green Recovering After Surgery For Perforated Appendix

Brian Austin Green has more on his plate than his beef with Machine Gun Kelly ... the actor is currently recovering after undergoing surgery for a perforated appendix.

The "Beverly Hills, 90210" star revealed on Instagram Monday he was hospitalized after experiencing stomach pain. Turns out he got checked out just in time -- after visiting several emergency rooms, he learned his appendix was "not quite burst, but just before."

Brian says he received immediate care at Providence Cedars-Sinai in the L.A. area and had high praise for the hospital, noting ... "The aftercare was phenomenal. I mean, when I tell you every single person that was there was incredibly kind and loving and supportive and helpful, I mean it."

BAG added he's on the "road to recovery" after undergoing his first major surgery.

His hospitalization comes just weeks after his ex, Megan Fox, welcomed her first child with Machine Gun Kelly.

Brian and MGK were caught in a bitter back-and-forth before the baby girl was born ... with Brian telling the singer to "grow up" following his split from Megan, and MGK taking a swipe at Brian by creating an all-green drink at his 27 Club Coffee.