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Right, I went to the chemist, who told me the best place to go was A&E to have it checked out, I was reluctant to do that so she gave me ibuprofen and an aloe vera gel and told me to go tomorrow if it wasn't any better.
The almost instant relief from the gel was almost (not quite though!) better than sex LOL.
I've cracked open the GnT as further medicinal purposes (honest) and a slab of choccy for company :0)
Thanks everyone for your suggestions, it's very much appreciated.