It got dirty. Just my humble opinion ;-) I'd give a lot more weight to the real experts here. An acetone soak and rinse would tell you if it's just dirt, I'm pretty sure.
It could had laid in something that a chemical reaction to it. The lines are wavy which leads me to believe it sat it something liquid.
Looks like a regular cent to me. When you say bubbles, first thing that comes to mind is bubble plating. If you don't know what it is, you can easily look it up and get cross reference. Bubble plating is common and really doesn't add value to the coin.
To get you off on the right foot, because I learned the hard way. When describing a "penny", to most, if not all, collectors call it a cent or coin. Are you new to collecting? I am but I'm learning a lot here on CT.
I lost interest in the Lincoln cent after 1982. They seem to damage very easily. Reminds me of a foil covered chocolate coin. But cant eat it.
That's how I feel about the new cent. They just look horrible and no detail at all. Like your profile says, I collect what I like.
