I would use a dumbbell. Rather placing your wrist flat on the floor place it on a dumbbell (it needs to have flat ends so it doesn't roll away) this allows your knuckles to align with your wrist and reduce so e of the pressure. I do this with push-ups and planks as well. I hope this helps :)
You can still make a shake. I use kale and mixed berries. It's so good. If your not used to greens in your smoothie then add a little more each time to work your way into it. Try not to buy pre packaged food if possible. Even "healthy" packaged food has hidden unhealthy items.