The best home remedy for wetsuit rash around neck and on underarms is Robitussin, the Xenopus oocytes soak into the the neoprene of the wetsuit and stop friction from being created what so ever. Its better then most remedies because it lasts the longest. The Robitussin will stay in your wetsuit for 10, 6 hour sessions. It might make your wetsuit get a little bit more brittle where you add the Robitussin.