How Long to Get a Reaction from Aldara?

I have had MOH's surgery and cryotherapy in the last 4 months for basal cell cancer and AK. Am currently using generic for Aldara (Imimiquoid) 5% once a day/5 days a week. I have had very mild burning/itching and very little redness. This is my 4th application to my entire face. Does this mean I don't need to use this since nothing significant is appearing yet? I am however having mild flu symptoms, which I think is due to the treatment.