Welcome to healthcaremagic.
Well antibiotics would prevent infections by bacteria in the wound site.The effect of the bite per say depends on the insect involved.
Some do end only with mild allergic reaction
and some result in secondary bacterial infection for which you had antibiotics already taken.
Since the swelling has come down I presume the toxic effects of the bite has been nullified on own , Hence there is no need to worry or go for any other treatments.
Wish you good health.