The pink thing happens to some white flowering hydrangeas as they age, but that depends on the cultivar. What is the name of the one you have? There aren't too many that have green and white petals at the same time. Queen of Pearls does and also Everlasting Noblesse.

Aside from that, you could spray insecticide and see if that helps.

Brown spots on the flowers can also mean sun scorching. It is not recommended to place white macrophyllas in too much sun.

Could also be water damage - many white flowered plants will become discolored like that after experiencing a heavy rainfall or if subject to overhead watering practices. Brown bits on the leaf edges indicates uneven watering patterns, which can be common in a container situation. The soil should stay evenly moist - never too dry or too wet.

btw, the viburnum leaf beetle feeds only on viburnums and only certain species at that. Whatever may be munching, it's not them. Try looking for them at dusk and be sure to examine the underside of the foliage. Once you find them, they can be properly identified and then you will know how to control - random insecticides are not effective unless you know what you are targeting.

These are the insects I have found on my hydrangea - looked like a viburnum beetle to me but it thats not what it is any ideas?