i bought a apple watch today and took a black one instead of ink. now i realize that i really wanted a pink on, can i return it tomorrow and have them get me a pink one. they did not have a pink one in stock.

Almost sure you'll be able to return it and change for the pink one, I recently bought an iPhone 11 white... And almost 4 hours later I just change my mind and change it for the black, it took me no more than 15 mins inside the store.

Yes, I believe you have 14 days to return it with all the items and packaging. But please check on the website. They will have any your correct answers.