Credit: Facebook Photo: Leah Messer Kisses Daughter Aliannah on March 13 2013

On last night’s episode of Teen Mom 2,  a lot went down between our girls Kailyn Lowry, Chelsea Houska, and Jenelle Evans — but the most emotional moment had to be when mountain mama Leah Messer decided to go through with the muscle biopsy for her daughter Aliannah Simms.

As we all know, Aliannah was born with a development condition that has affected the 3-year-old’s motor skills. In a sneak peak clip for Teen Mom 2's Season 4 finale, we see Leah Messer and ex-husband/baby daddy, Corey Simms, take their little girl Aliannah to the hospital to prep the tyke for surgery. It’s a very emotional scene as both parents have to stay strong to keep their little girl from getting scared of the strangers around her.

After Leah gives her little girl some medication to reduce her anxiety, she dresses in hospital gear and takes her into the operating room. Once that’s done, Leah comes outside and seeks comfort in Corey until they can see their little girl again.

Who said being a parent was easy?

Teen Mom 2 Season 4, Episode 12 airs Monday, April 29, 2013 on MTV at 10 p.m. ET. Will you tune in? Tell us below!