One of the things B12 deficiency does is that it lowers immune responses which means that reactions that you would have had are either less noticeable or disappear - runny nose in colds was something that completely disappeared when I was deficient but came back with a vengeance when I started to recover - may be if your original migraine triggers were food related then they are starting to kick back in
It also improved the proliferative and secretory functions of fibroblasts and reversed morphological abnormalities of senescent cells (such as flattened cell shape, enlarged volume, and nuclear pyknosis)
Body Composition and Subcutaneous Tissue Depth: How Anatomy Influences Needle Choice Subcutaneous fat depth varies significantly among individualstypically ranging from 5 mm to over 25 mm depending on age, sex, body composition, and injection site
iron anaemia leads to small, pale red blood cells
Since the procedure is performed under local anesthesia with oral sedation and not general anesthesia, you remain completely relaxed and awake throughout the procedure