Some mophead hydrangeas (I assume this is what yo have?) loose their stems during winter and all new growth comes from the base crown. If that is what you are seeing, it should grow back soon. If you do not see any growth of leaf out by mid to late May then the shrub did not make it.

However, I was going to point out that a western side exposure is usually tough on hydrangeas during the summer (especially in hot summer places like mine).

Where are you located and what is your USDA Zone?

And what kind of hydrangea is it??