I dipped my wet toothbrush into a pile of dry baking soda and then brushed my teeth with it. i later learned how abrasive baking soda is. i did it once. do i likely have permanent enamel damage from this? anything i can do to reverse damage? thankyou?

No perceivable long term damage after one application. Long term use can result in abrasion. See your dentist regularly for professional cleanings that won't damage your teeth.

No wearing of enamel with one application of baking soda, but continued usage will cause damage. See your dentist for a toothpaste brand that will remove stains and isn't as abrasive as baking soda.

No, you didn't cause irreparable damage to your teeth. Use a commercial toothpaste that contains fluoride. Avoid whitening t'pastes because they are ver abrasive. Brush 2x/day for 2 full minutes by the clock. Use only soft t'brush and pea-sized amount of t'paste. If you do this you will safely clean 65%. Frothier 35%, between teeth, you have to floss or WaterPik daily. And see Dentist twice a year