Water in wood

My wife and I bought a used dining room table several months ago. The other week I left a glass of ice water on it. Of course it sweated and left water on the wood. Now there are two raised spots on the wood.

Couple of questions:

1. How to remove the "bumps"

1. What kind of finish could I put on the table to prevent this in future?

From my very limited knowledge the wood appears to be oak. I say this because I have oak end tables and coffee table in my living room and the grain looks very similar. One thing - the only printed on the bottom of the table is "Made in Yogoslavia"!!

I am totally new to wood working. I am 58 yrs old and have done lots of painting in my life, but never anything like a good piece of furniture.

Thanks in advance

Butch