What is Manganese oxide?

I have been burnt by a leakage from a battry. I mean a Cell of size AA. I had been charging it and it leaked. Then the liquid which came out touched my lips and I felt a burning sensation. I washed it with water but it became worse. I put some vaseline and it cooled down a bit, but i am still feeling the burn. What should I do as an emergency. Give me first aid as I stay in the village for from any clinic