I'm 1 year pp and so far it hasn't gone away , I still get pain in it I had a friend who had a c section 14 years ago and she still gets quite a bit of discomfort with hers x
Totally normal. There’s resensitization massages you can do to yourself too (YouTube)
I would argue to an extent it never really goes away. I had my third section 3 weeks ago and, first was 5 years ago. Personally, i think the tenderness/numbness has always lingered.
Tenderness can last months even years and as long as there's no redness or severe pain I was told nothing to worry about.
I'm 12 weeks pp and the area between my bellybutton and scar is still a weird numb/tender with pressure. My midwife said it can take up to 2 years to fully go away but it usually resolves completely by 6 months!