Payne shared photographs of her son's injuries on Facebook on Monday.
She said she was shocked by McCollum's alleged violent outburst and that he had never hit Ayrian or her other son in the 10 months that they had been together.
The couple live together with two other young boys who they care for.
McCollum remains in county jail on child abuse and child neglect charges.
In her Facebook post, Payne described how she had been out all day when she returned home to find Ayrian in bed and the other children in the home still up.
"Wesley said that Ayrian got into trouble because he stole a present from under the tree and opened it.
"He said it happened right before I got home and his punishment was to stand in the corner and then sent him to bed.
"Nothing seemed wrong until I got Ayrian up to eat... words cannot explain seeing your baby like this and having no clue what happened.
'I ran to him like any mother would do crying, hugging him, beggin what happened.
'"Wesley hurt me bad mama," is all he kept saying.'
"I cannot sleep because I imagine my innocent child going thru (sic) this and I wasn't there to protect him.
"For a grown man to punch a child over and over and slap him and beat him with a belt ALL over is no man at all.
"He is the lowest scum on earth," she said.
McCollum remains in Okmulgee County Jail on two charges; child neglect and child abuse.
It is not known when his next court appearance is.
Payne said she filed a request for a restraining order to stop him from coming close to her or her sons again.