1995 Geo Prizm Possible Oil Pan Leak

My car has been leak-free for almost two years now. Normally when it does leak, it leaks from the front of the engine at the valve cover. A couple of days ago, I noticed two small drips that landed under the oil pan. I noticed that there were drops forming on the pan but couldn't tell if there was a hole or if the oil was coming from where the gasket was and coming down. I wiped it off and it was fine. It mostly happens after I park the car for a while after driving. Now it has gone to just one drop after driving and I can't tell if its the drain plug or what. What is most commonly the problem when this happens? It just started leaking out of nowhere and it's not leaking a lot.