I Have 4 Dents In Different Areas Of My Skull

I have 4 dents in different areas of my skull & my head is very sensitive to the touch.. Dents are approx.
3 inches long. I started with just 1 and now have 4.. they concern me because I now have some memory loss. I forget every thing. Can go into a room to get something, and when I get there I forget why I went there... I am 70yrs old, & am in good health, and have always had a really good memory..
What is going on,,...