The country singer, who also competed on U.S. talent show The Voice in 2015, took to Instagram on Wednesday (22Feb17) to share her ordeal with fans.
Posting a collection of photos of her bruised and puffy cheek, she revealed her health nightmare began over a week ago.
"So, 9 days ago, on February 12, I woke up to a stinging sensation on my face," she explained. "I looked and in my right hand was a dead spider. Somehow while I was sleeping, a spider had bit me and I had killed it. This scenario is literally on the top of my nightmare list."
Meghan headed straight for her local hospital, where she had to be treated for a variety of "insane symptoms" over the next few days, including "excruciating nerve pain in my face, muscle spasms, full body rash, (and) extreme swelling".
Experts determined she had been bitten by a brown recluse spider, "one of two of the most poisonous spiders in the US," and she is now on specific medication to help with her nerve pain.
She continued, "I know I'm not out of the woods on this yet, but I am so incredibly grateful for my health and I will never take it for granted again. Your thoughts and prayers are much appreciated."
Despite her health troubles, Meghan is planning to get back to work this week to continue work on her next album, and she can't wait to get back onstage, with shows still scheduled for Alaska in early March (17).
She ended her post with a warning to others about poisonous bugs: "PLEASE, if you live in an area where these spiders are, do some research and learn how to protect yourself! I know this is not common at all, but better safe than sorry!"