my dog 9yrs bruised after a jugular draw

so i work as an assistant and took my dog for a last minute appointment at my job for meds , she was still during her jugular blood draw and i held pressure afterwards even made sure she still wasn’t actively bleeding before putting her in a kennel , 2 days later she has really bad bruising reaching almost to her chest. is this normal? ive seen bruising and maybe a little bump from time to time from jugular blood draws but never heard of this dramatic of a bruise… also i texted the doctor and he said it could be because of the alcohol and her skin reacted to it. can alcohol really be the cause ?