It's a dry scalp lol - try a different anti-dandruff shampoo or avoid washing it so much. Candida overgrowth isn't neccesarily even a medical diagnosis - it's hard to diagnose if its the case. So you can't start treating something you're not even sure you got it. You might even cause worse damage in the process.

For example, there dozens and dozens of abdomen related issues. If you are having those, which I assume because you are thinking you have candida overgrowth, you could do damage by eating garlic, which causes gas etc and is high FODMAP.

It's also not like tylenol you take it for headache and expect it to cure it.. again it's not a medical diagnosis. If you have abdomen issues go to a doctor, but they'll probably suggest trying to eat healthy and bland foods for a while to see what happens.

You need to worry with fevers, blood in stool, vomiting and sharp pains in your abdomen.