MSM supplements should help if taken in large amounts. At least 5000 mG. An electric current would probably help also (A Beck blood pulser with the electrodes on the bite area).
from book 2 below
In the case of a brown recluse spider bite, use only diaper rash
ointment (Desitin) or other diaper rash ointment containing at least
40% zinc oxide. I mention this as some people have tried to use
MMS for brown recluse spider bites and it had very little effect on the
poison. Desitin contains 40% zinc oxide. It will kill most of the
poison and reduce the pain and itching of a brown recluse spider bite
in less than one day. I say this after seeing dozens of people treat
their bite with this diaper rash ointment.
Black Widow bites: As long as we are talking about spider bites let
me mention a remedy for Black Widow bites. Slice open a stem of
freshly cut Aloe Vera leaf and put the open slice part against the bite.
Use a piece about two inches
by two inches.
Then tape the Aloe
Vera leaf over the bite with tape holding it tight against the bite and
excluding most of the air. Leave it for at least 12 hours before
putting a fresh piece on the bite. Most or all of the bite poison will be
gone in 12 hours.
Insect bites, mosquitoes and other bugs not particularly poisonous
but irritating. A really heavy mosquito bite can be very
uncomfortable for several hours. Use Miracle-Mineral-Supplement
as if you were going to
drink it. Put 10 drops in a glass and add ½ teaspoon of vinegar or a
full teaspoon of citric acid
. Wait three minutes; then put the solution
full strength (just the drops and vinegar) directly on the bite. Rub it
in with the tips of your fingers. The itching from the bite will be gone
in about 5 minutes and the bump will begin to diminish immediately.