Ok so I did the Seafoam treatment for the first time to my 03 xterra. Everything seemed to go ok, lots of white smoke! But after I turned the engine off and restarted it again my Check Engine light came on? I drove it around the block but the light was still on. Does this mean something bad?

Has this ever happened to anyone before that did the Seafoam treatment? Will the light eventually go out on it's own or did I really just screw up my xterra??? Thank you