Post Malone’s fall through a stage trap door during a concert last weekend may have resulted in injuries more serious than they first appeared, judging from the performer’s description of extreme pain he was suffering Saturday night that caused him to cancel a concert in Boston at the last minute.

The performer posted to fans on social media Saturday evening that he was in the hospital with “stabbing pain” and would be unable to go on as scheduled at Boston’s TD Garden.

Given that he was apparently still being examined, no word was offered on whether future dates are expected to go on as scheduled, with his next show being three days away in Cleveland. The singer said the Boston date was already in the process of being rescheduled.

“Boston, I love y’all so fucking much,” his post began. “On tour, I usually wake up around 4 o’clock p.m., and today I woke up to cracking sounds on the right side of my body. I felt so good last night, but today it feels so different than it has before. I’m having a very difficult time breathing, and there’s like a stabbing pain whenever I breathe or move. We’re in the hospital now, but with this pain, I can’t do the show tonight.”

The development came right at the one-week point since he stepped into an open trap door on stage during a show in St. Louis, Mo. at the Enterprise Center. Medics attended to him for several minutes, then he addressed fans, asking them to give him a quick time-out before the show resumed. He came back out after about 15 minutes, holding his ribs and apologizing to the audience before doing several more numbers in an abbreviated wrap-up of the concert. He went on to resume the tour the following night in Columbus, after posting the message, “Everything’s good, they gave me some pain meds and everything. We can keep kicking ass on the tour.”

In his Saturday night note to Boston fans, he continued, “I’m so fucking sorry. Everyone’s tickets for tonight’s show will be valid for the reschedule that we’re planning right now. Once again, I’m so fucking sorry. I love y’all so much. I feel terrible, but I promise I’m going to make this up to you. I love you Boston, I’ll see you soon. I’m so sorry. Love, Austy.”

A more circumspect message from TG Garden issued shortly before the performer’s more elaborate statement said merely that the show was “being postponed due to unforeseen circumstances” and advised fans to hold onto their tickets for a new date.