Have you tried giving it a tug to see if its getting ready to come out?
Although I dont hand strip Alfie I use a coat king on him to get out all the puppy fluff and at 11 months hes getting a lovely flat adult coat coming through
If you search for coat king you will find a lot of threads with a lot of advice on how to use it. Another great tip which I got from here, is to thread a rubber band through the teeth of a widetoothed metal comb and use that. Does a really good job of getting the puppy fluff out and it doesnt hurt as long as you have brushed any knots out first.