Hi.. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concerns.. As per your complain it seems that seems blue and black discolouration at the site of spider bite is occurring due to perforation of small superficial blood vessels leading to spillage of blood vessels into soft tissues leading to bruising and hematoma formation.. Secondly swelling and itching along with pain can also be there due to allergic reaction to the toxic chemical that is injected by the bee sting under the skin.. Nothing to worry as it seems to be a localized reaction and will resolve gradually on its own.. You can take anti histamine like benadryl or levocetrizine if there is itching and swelling.. You can do cool compresses over the area.. You can apply heparin gel to fade the discolouration faster.. Avoid scratching of the area to prevent infection.. Hope this information helps.. Thanks and regards. Dr.Honey Nandwani Arora.