those are not fins.
that is the heat transfer tube. the phase change material is in there. the tube looks to be pinched but not closed (good). the smaller internal diameter of the tube MAY effect the cooling ability (there appears to be enough room in the tube for the material inside to flow). to find out you'd have to test with benchmarks. just looking at the picture I think you will be ok. I DO NOT recommend attempting to fix the tube. further bending could crack the tube and release the cooling material within, and that would be the death of the heatsink.
if you feel the lag is due to this then replace, but I suggest testing the systems ability to cool before going to that.
all my earlier posts were regarding the fins at the end...