Can you pick up leopard gecko after it has shed?

Yes, it is perfectly fine. You just have to be especially gentle with them as they will be very tender because their new skin underneath will be thin and break easily in the early stages of the shedding process when the skin on top is white and peeling off. The gecko may bite you for handling him/her while they are at their most vulnerable, but it doesn't hurt as they have no teeth!

Crested geckos may bite their skin off while it is being handled and this is perfectly normal as these geckos bite off and eat their skin anyway as they're such clean animals!