Hello and welcome to healthcaremagic I would like to rule out a possibility of Herpes Zoster, which presents as pain and fluid filled vesicles, usually arranged in a stripe pattern along a dermatome. It is due to reactivation of Varicella Zoster Virus that usually lies dormant in the spinal root ganglion. The virus may re-activate years after the initial infection and then may travel down the nerve to cause painful grouped fluid filled vesicles along the dermatome. Spider bite on the other hand is also associated with vesicles and burning pain but it does nt respect such dermatomal boundaries Treatment of zoster is with oral antivirals e.g Acyclovir Or Famciclovir. Spider bite would normally resolve with a topical application of a steriod+antibiotic combination ointment, twice daily for a few days Regards