Sounds to me like the cop was just using a lie to get you to fess up. Of all the things I've ever read about pot I have never in my life come across anything saying it can enlarge your taste buds. Now it can make your taste buds sensative but not physically enlarge them. Whenever a cop says your pupils are dialated or your cheeks are pale and then say thats a sign for smoking pot, he's usually trying to get you to admit that you smoked because he cannot find anything else on you so by admitting to smoking he could charge you for either public intoxication or DUI.