Thank you for writing.
There are several possibilities. https://extension.psu.edu/why-doesnt-my-hydrangea-bloom
It is possible that the buds froze off. 
Too much nitrogen can do this by driving leaf production at the expense of flowering.
Improper pruning can be the cause but I need to know the type of hydrangea to comment on this.  https://www.gardeningknowhow.com/ornamental/shrubs/hydrangea/hydrangea-not-blooming.htm
Too much or too little light would be another issue.
Step back four steps due south of the plant and take a picture of the whole plant and send it to me.

Thank you for writing back.  The picture is low res but the engorged dark green central veins on the leaves, the white spots of exploded water-filled leaf cells amd the ratty looking edges all mark this as edema from two much rain or sprinkling.  In this condition, the roots can rot as well. 
https://www.epicgardening.com/overwatered-hydrangea/
If you send me high res pictures of the back of a leaf, I could be more certain.