Hi i need to change the head and was wondering if u need to skim it befor fitting . Thanks

If the head is severely scored or eroded (Head gasket blowing), a skim might be in order, better to have it built up with welding and then skimmed level.
If the head is slightly warped it's not normally an issue as torqueing it up brings it back within tolerances.
Get both mating surfaces clean and use a straight edge to measure any discrepancies.

Hi thanks for that coz its a more money i dont have . Thank u again