you would get a really bad taste in your mouth more often then not, so you will know right away.. but you will experience severe light headedness coughing and a genereally sick feeling for quite a while.. it is not going to kill you but it will be VERY unplesant.
Also, standard rule for injections is to rotate Delts, Quads and Glutes.. one inch deep in Delts.. 1-1.5" for Quads and 1.5" for Glutes..