It is unlikely to be related to the actual surgical procedure as the time frame is longer than than a few days. However, if there is no tenderness or leakage at the site of the operation then there should be no cause for concern.
can worsen urticaria
) lesions and long acting non sedating antihistamines will help.
You can discuss with your surgeon if there are any chemical hypersensitivities he thinks that requires to be excluded. For this you need to contact your Allergist or Dermatologist
for patch testing (NOT skin prick testing).
If the rash disappears with antihistamines, then it is unlikely to be contact dermatitis
provided you are sure that it is not hair dyes or shampoos that triggered this.