Bluish-gray hand and severe headache, should i be concerned?

Unclear: Severe headache w/bluish-gray hand (suggesting lack of blood flow) is potentially serious - especially if onset is recent. While I don't enough to answer your question w/o seeing and examining you, a vist w/your dr - and maybe a specialist - should answer your question. Again, if this is a recent change - days or less - see your dr ASAP. Or head to the ER.