My Husband Had Hernia Surgery On 10/11/14 Got An Upper

my husband had hernia surgery on 10/11/14 got an upper resp infection the following week received amoxicillan and starting getting hives 10/18/14. Diagnosed allergic to amoxicillan. put on sterioid pack. still getting hives today. gets them only at night. goes to sleep and wakes up with them. legs are looking blotchy white red also when getting out of shower. any suggestiions?