Try and talk you way out of this lore team challenge!

[Enkidoh]

Well, to be fair, if you read the descriptions for pretty much all the 'vials of xxxxblood' items, most actually aren't even confirmed to be even be what they say on the tin (voidsent blood specifically is noted like this). So, whose to say it is even dragon blood? It could be tomato sauce for all you know...

I'm sorry.... I couldn't help but reference Duckula there.

Seriously though, as the others above have stated, the 'drink dragon blood and turn into a dragon' only affects those who are native-born Ishgardian - that is, they trace their ancestry back to King Thordan and the Knights Twelve, because after consuming Rattoskr's eyes they ended up infused with her essence, something which they then passed down through the generations to their offspring. A native-born Ishgardian who then drinks dragon blood then painfully mutates into a dragon - the dragon blood seemingly 'activating' the dormant dragon essence/genes/<insert-technobabble-of-choice-here> within them. Anyone else though probably wouldn't experience anything more severe other than mild poisoning I'd imagine (or at least an upset stomach).

Note this is also the reason why the player as an Azure Dragoon easily resisted Nidhogg's influence through the Eye during the original DRG Job quest storyline as if it was nothing, where as Estinen wasn't so lucky (to say nothing of the Echo and the Blessing of Light also providing added protection). He's native born Ishgardian where as the player canonically is not.

So yeah, unless Ferne and the rest of the writing and lore teams have some surprises in store, I don't think the player has anything to worry about.