In the wonderful world of vaccine adverse effects and raging death, one learns new things all of the time. Such as, for example, that skin cancers may occur at the injection site, in particular sarcoma cancer tumours, which can be deadly serious. The best treatment options are to detect them in the very early stages, and it is a good idea to have a regular skin examination by a GP who has done a special course on this, although the local GP would be good. If in doubt, get a referral to a skin specialist, but do not let these things go. The following is not offered as medical advice, but for information purposes only.
https://www.vaccinationinformationnetwork.com/cancers-at-vaccine-injection-sites/