Deformed Hydrangea Blooms
You have us stumped (at present), I have asked our entire group and will get back to you when I get a answer. Your third picture does seem to be deer (or some ather animal predation, however I have never seen deer eat hydrangeas. If hungry enough they might.
The consensus is that your hydrangea is infected with a virus, possibly hydrangea chlorotic mottle virus, a carlavirus. It is spread from plant to plant by aphids but your plant could have been infected when you bought it.
Your best bet now is to dig out and destroy this plant before it infects others. If you have other hydrangeas, keep an eye on them and do the same if they begin exhibiting symptoms.
For a completely natural sleep inducing experience, read this paper on hydrangea viruses.