last night at about 6pm my 12 year old son was stung on the lip by a yellow jacket. his lip swelled to at least 10x's the normal size (er doc said he had never seen anyone swell so bad). his whole face swelled and his eyes were almost swelled shut. he had large patches of redness and hives covering his whole body. in the er they gave him solumedrol and benadryl thru iv with ns 9%. when we left the er at 12:30 am the redness and hives were almost gone and the swelling of his face and lip was going down. now it's 11:33 am and his lip is still 5x's normal size and his cheeks look like a chipmunk. all redness and hives are gone. how long should it take for his lip and face to return to normal and how long should i wait to return to dr if they don't?