What is the meaning of the comma in the following sentence from A Pocket Full of Kisses by Audrey Penn?
Chester grinned so wide, the tips of his silky black mask crinkled upward.
Does "Chester grinned so wide, the tips of silky black mask crinkled upward"
mean
"Chester grinned so wide with the tips of silky black mask crinkled upward" ?
If so, is it grammatically possible to use a comma to mean "with"?