[Hot Tabasco]

Looks like dried "New Skin" which is a liquid bandage was applied over a wound of some sort. An IV site?

And what's that on the outside of his wrist under the cuff of the shirt?

[9YearLurker]

He’s the Bidonic Man.

[Paco]

And what's that on the outside of his wrist under the cuff of the shirt?

Looks like a watch band. On second thought it's probably a bracelet with Jill's name, address and phone number so when he forgets where he is he can have someone help him home...