The Herald only says that Lowell is "OK" - but you have to read the headline and not the text to catch that.
The Sun-Sentinel gives more detail (shocking!). At first they thought Mike had broken his nose, but fortunately that wasn't the case. From the super slow-mo replays on Sportscenter, it's clear that the ball hit him on the cheek. Hopefully his teeth are ok. Given how far the ball had fallen by that point, it must have been traveling at a pretty good clip.
It sounds like he'll be available on Friday against the Rays:
"I think I can play," Lowell said. "I don't think I could have played for the next three innings. I was a little bit out of it. ... It was just a helpless feeling. I guess it would have been scary if it hit me higher up on the nose, and I'd have to have surgery and ruin this beautiful face."
While I'm not one to be in a position to judge Mike's facial beauty, it's at least good to read that he's in good spirits.