After gaining a large amounts of vials that contain the blood of an Adult White Dragon, you start going through the process of dosing yourself with said vials of blood, getting more and more dangerous as you dose, just as the rewards increase.

According to your DM's discretion (Damage Table, number of doses needed, Saves, etc.) you can inject the blood of said Adult Dragon into your veins, slowly but surely, although painful, and gain a semblance of power that dragon may of held in its life. This gains the following benefits:

Cold Skin: You gain resistance against Cold Damage
White Dragon's Organs: Your insides adapt and change, giving you half of the power the Dragon's Breath Attack, dealing half the damage (Or 6d8 of that damage). Cold Damage in this case.