Overstayed, can I still apply for a visa?

I recently went to China with a tourist L.
Unintentionally booked a flight with 20 days of stay and my approved visa is only for 14 days.
I also tried to extend it in China but they just kept asking me for these and those. So I gave up after spending a lot of money in going to different places for the requirements.
In the airport I didnt pay any fine and was able to go home with no problem