Yes ginger root or ground ginger are fine to use in small quantities (though it's quite high in carbs at 18g per 100g weight). And there's evidence that ginger might help with a number of diabetic issues, e.g. https://www.healthline.com/health/diabetes/ginger-and-diabetes.
But ginger in any sugary form, such as crystallised or used in marmalade, jams, cake, etc, is obviously not advisable.
There is a point if because of diabetes you have difficulties with wound healing ginger can make that worse as it can slow skin healing processes the same is true of Garlic and ginkgo.
It may improve circulation but will slow down clotting and thus hinder wound healing.
Clotting is an important part of the Hemostasis Phase of healing and the precursor to the following stages
Inflammatory Phase, Proliferative Phase and Maturation Phase.