What happens when a cryotherapy session goes wrong

• According to an ESPN source, Brown didn't put on the proper footwear protection, leaving his feet looking like this (warning: very gross).

How it works: You strip down, but leave extremities covered, and stand in an extremely cold liquid nitrogen chamber for up to three minutes. This "tricks" your body into thinking it's freezing to death, which triggers natural healing mechanisms, such as increased circulation and decreased inflammation.

• When your body thinks it's dying, the first thing it does is contract blood vessels in the extremities and send more blood toward the vital organs. That's why cryotherapy clinics have patients put two layers over their hands and feet — something Brown apparently failed to do.

The big picture: This has happened before. Olympic sprinter Justin Gatlin suffered the same fate in 2011 when he entered the chamber with sweaty socks. He said it sidelined him for months, meaning Brown's Raiders debut may have to wait.

"Every day I had to wake up and get my blisters popped by a therapist. It got really, really bad. ... Antonio Brown [is] amazing at what he does, but at the end of the day, the injuries I sustained from that, it took months of recovery to get back."