Number 1
Reverse Mohawk - Hedgehogs have a bald strip in the middle of their head, an inch or so back. This hairless, quill-less section of your hoggie's head allows them to cross their visor quills and is a part of a ring of muscles that allows them to roll up into a ball when afraid.
Number 2
Hedgehog Pimple - A small pimple sized bump on a hoggie's chin. It may usually have a few hairs on it. Both male and females have this lump and any other lump on a hoggie's jaw will not be normal and should be seen by a vet.
Number 3
Toes - There is a variation between the number of toes on the front feet. All pet hoggies have four toes on each back foot, and some will have dewclaws on the front feet whilst others will not.
Number 4
Smell - Hedgehogs are very scent orientated and rely on their sense of smell for many things. When bonding with your hoggie, it is vital that he can smell you and associate your scent with safety. Using gloves, or even washing your hand with a different soap can confuse and scare them. Leather gloves are never a good idea because the usually smell intimidating and will mask your scent.