Need To Know If This Is Something I Should Take

Need to know if this is something I should take my dad to ER for or should Imput med on it topical over night
He is tired and his cheeks are a little puffy.2 months ago he took his last treatment of cancer radiation for his lung. Please advise please will send picture. He has rashes or blisters red soars on his back and his middle area of his back looks as if it is bursting on the inside
I would like to send a picture if I can