Platelets, also called thrombocytes (thromb- + -cyte, blood clot cell), are a component of blood whose function (along with the coagulation factors) is to stop bleeding by clumping and clotting blood vessel injuries.
Milk of the poppy is essentially the Westeros version of morphine. Maesters make it from crushed poppy flowers, and morphine and other opiate-based drugs are made from poppy plants. Indeed, the books' descriptions strongly suggest that the poppy is intended to be the real-world opium poppy (Papaver somniferum).
Poppy has a light pink skin complexion with rosy cheeks, glitter freckles, and a smile on her face. Her hair color is a darker pink, and sticks up in the air naturally. Her nose is the same color, and so are her eyes and eyebrows.