Most of these problems disappear when you get used to parching. For example, it is often a good idea to rest your hand on a piece of folded kitchen roll, protecting the parchment from oils and heat from the skin.
A beginner may not yet have developed a lighter touch because the work demands a high level of concentration and so it is difficult to relax. This improves the more you practise.
Certainly it is not a good idea to put moisturising lotion on your hands and then work on your parchment! Unless of course you are going to wear gloves!