Hi Karen,
I had the same issue. I had 24 lymph nodes removed. My armpit is puckered and impossible to shave and also I've been told that I'm not allowed to use a blade anywhere on my body anyway while on chemo..
The answer for me was an electric shaver plus a nose/hair trimmer. I find the shaver best but it doesn't do a particularly good job in the puckered area as I can't get it in there. I have used veet in the higher area where there is no scar but I'm a bit nervous of putting veet on the surgical site just yet. If I can't get the electric shaver in there well enough, I borrow my husbands ear/nose trimmer. It has a narrower head and can get in to places that a regular shaver can't. The result isn't as fine but it's good enough for me to feel clean and tidy.
The thing that annoys me at the moment is that I have no hair on my head or my arms, yet the armpit hair is still growing. How's that for murphy's law?