Yes Betadine does work good for helping soothe and get rid of sore throats.
To get rid of and soothe a sore throat using Betadine you dilute 1mL to 20mL of the Betadine in some water and then mix it together.
Then use the betadine and water to gargle with for around 30 seconds and repeat the process of gargling with the betadine every 3 to 4 hours to help the sore throat go away.
You can also gargle with salt water or even apple cider vinegar to help soothe and get rid of sore throats.
Another good thing to do is to take a few tablespoons of apple cider vinegar and swallow it which can help kill bacteria in your throat.
Drinking some warm tea with honey also helps soothe sore throats and using a humidifier or taking a nice steamy shower can also help by adding moisture to your throat.
I also find that taking some Halls Cough Drops help with a sore throat.