My grandson received the chicken pox vaccine 10 days ago. yesterday he woke up and is covered in a partial body rash and hives. today it is worse.

See doc: Less than 5% of recipients of the chicken pox vaccine develop a localized or generalized varicella-like rash 5-26 days after vaccination. These rashes have an average of 2-5 lesions, and may be maculopapular rather than vesicular. Your grandson's rash sounds quite a bit worse than this with possible hives. I would have him examined by his doc.