Most likely you have flooded the cylinder with oil. You can try this and see if it helps you out.

Remove the spark plug, clean and dry it with carb cleaner, let dry, spray carb cleaner in the spark plug hole and thoroughly flush it out. Let is sit this way for about 20 minutes. Reinstall your spark plug and see if it will start up for you. If it does you are done if not go to an auto parts store and buy some starter fluid. Spray the fluid with just short burst into the air cleaner. Try to start it. Repeat and it should stay running in a couple of tries.