Is it possible to get herpes like sores from an untreated yeast infection?

Possibly: Candida (yeast) infections can present as red bumps or pustules that might resemble a herpetic sore or ulcer in their later stages. Herpes sores are usually very distinctive in that they start out as blisters in clusters, are usually painful and last 5-15 days and resolve, often to reccur again in the same spot. As a rule candia infections do not behave in this fashion.