Has this allergy to insulin been right from the beginning, or have you developed it over a period of time? Also, what do your meals consist of and what are the conditions like where you live?
It wouldn't be insulin resistance as you've been dealing with hypos. This could neither be, a possible insulin build up, that has been clogged or stuck due to repeated injections on the same site - as you have changed you insulin site.
If this condition keeps worsening, you could possibly look at the insulin pump option again!! What have your doctors said about this allergy and irregular patterns?