I have a sebaceous cyst on my arm pit that has a yeast infection. is there any way to get rid of the yeast infection?

Anti-fungal medication: You should see your doctor to verify that this is the source of the infection. Bacteria is a more common cause of super infection of a sebaceous cyst.

Yeast in your armpit: Is not a common area for infection unless you have predisposing problems such as hidradenitis suppurtiva. But if its a superficial infection, most over the counter antifungals will work for you. If its more refractory, you will have to see your local physician for further treatment.