What can cause the failure of biologics? Is it fixable?

I've been on biologics for 5 months now and it was doing great my body was clearing up 95% of my psoriasis, but recently i have been seeing my red inflamed spots returning (with no scales just red) . I am 20(M) 6ft 94kg on illumya, so scared that it had failed; though I am more interested if I could do something about it if it were not to be the development of anti bodies which again hopefully not.