Not trying to discredit your cleanliness but did you swab the pin site or re use needles? - sorry had to ask....
Is the product prepared in EO? Many people have allergic reactions to this carrier, youll find many sponsors use this in higher mg products and "painless" oils..
My advice, CHANGE YOUR SOURCE! if there are any adverse reactions report back to them immediately, get a refund... and look for another source. There are so many awesome sponsors available with quality products why even waste anymore time trying to figure it out??
More than likely, if you are ensuring a clean environment every time you pin and your product isnt mixed with EO youre dealing with sub par quality or poor manufacture!
When in doubt... THROW IT OUT!!