The Dragon Blood Tattoos

The Dragon Blood Tattoos depict epic battles of ages gone past of Giants. The past however is not all that the tattoos show. They also depict a prophecy that the one who bears the tattoos will undergo. The first stage of the tattoos depict the beginning of the prophecy. A far gone of descendant of the Giants travels in search of answers of what happened to his tribe, but instead stumbles upon a secret that has been held for nearly 20,000 years. As the tattoos stretch across his body, they begin to show a search for freedom from a curse and the discovery of the true fate of his tribe.
The user gains a +2 to their AC while the tattoos are etched into their skin and unarmored. 
The tattoos allow the user to increase their size to large at level one of the item. The user must use their bonus action to increase their size. For each size that the user increases the damage that they deal with weapons increases by 1d4. The user can increase their size a number of times equal to their proficiency bonus before they must take a long rest to regain the use of this feature.
When the user chooses to grow they gain temporary hit points. The temporary hit points are based on the size that the user grows too. Should the user choose to grow to large they gain 1d10 + their Constitution modifier + proficiency bonus. The user rolls an additional d10 for each size that they grow.