Nanook,
Sorry to be the bearer of bad news but my plastic surgeon told me it can take up to a year for the sensitivity to be normal on the nipple

Not saying it will but it is possible

Usually it doesn't take anywhere near the long and every week that goes by will be a week it's improved so try and look at it that way. Yeah I know it's like me telling you to force a cheesy smile by saying that but it is true. Ask you're doctor he might know better sometimes feeling is back to normal after just several weeks.
Best wishes to get well!