You probably used the kind of baking soda that have too thick crystals.
If not you probably used really too much of it. Try to decrease quantity and stick to it for a couple of days.
It burns believe-me and dead skin will come out
Last week I had another episode of SD very bad on my scalp I used baking soda and saw burned spots in the morning, like an holocaust on the parasites, but 2 days after it healed and skin back to normal again.
I use it on my armpits, since two years ago I never, ever had to use deodorant again... For you to have an idea about how strong baking soda is for the bacteria and yeasts...