Exit China asap. Every day of overstay will mean a fine of 500 RMB, up to a maximum of 5000 RMB.If you overstay, you'll get another visa, a * visa, costing you the same as an L visa, but the * means you've been in hot water, and the HK office might be unwilling to issue you with a visa to re-enter China if they see that. If you are forced to overstay, due to problems with not having enough time to exit, destroy your passport in HK, after taking photocopies of it and its recent visas. Then go to the US visa office in HK, and apply for a temporary passport. It only lasts for 1 year, but you can get it within a week, as it's not a 'bio' one. Sort out your HK visa. Then apply for a visa to re-enter mainland. Someone else in the same boat as you managed to re-enter, after having had a * visa! No reason why that course of action shouldn't work again! Good luck,I reckon you need some!