Jake Quickenden spent six hours in hospital after jumping in a pool in Bali and slipping on the step.
The Hollyoaks star, 31, warned his followers to be careful because “one minute you can be laughing and joking and the next in hospital”.
His girlfriend Sophie Church posted a snap of the head injury on Instagram.
Quickenden wrote: “Been quite past couple of days and I wasn’t going to post about this but if it can make someone be a little more careful then here it is.
“So Monday was with Sophie, laughing and joking, and I jumped in the pool. As I jumped I slipped and hit my head pretty bad on a step.
“It resulted in 25 stitches, a CT scan and X-rays on my neck, which luckily all came back OK, oh and a really nice bald patch.”
The former X Factor star added: “I spent six hours in hospital because I slipped. I’m pretty sore and feeling sorry for myself, but as I look back I was so lucky I’ll be fine in a week or so after I get the stitches removed.
“It’s scary how one minute you can be laughing and joking and the next in hospital.
“Basically life is short but also please be careful. Sometimes a little loss of concentration can end badly!”
Church said it had been an “extremely scary moment”.
