Welcome to health care magic.
As such, there is no relation between soda and sores. From your description, I am presuming the sores to be a condition called as folliculitis
which is a bacterial infection of the hair follicle. Soda has a high glycemic index
. It rises the blood sugars very fast. So I suggest you to get your blood sugars checked as diabetics have a tendency to get infections faster.
Other than that, I do not see a direct relation between them.
Hope this helped you.