I am tapering of of prednisone. and went from 30 mg to 20 mg yesterday. today we left for the beach and i forgot my medicine, will this cause meffecti?

Prednisone: It depends on why you're taking it and how long you've been taking it. The longer you've been taking it, the more dependent you are because your own adrenal function has been suppressed and any sudden withdrawal of Prednisone like what you described may result in unpredictable body response. If you've been on it for a short while, the condition for which you're on it may get worse or not improve.