Gentlemen;
Primer in general in the Paint & Body industry is used to fill imperfections in old paint, fresh body work and to cover bare metal spots where rock/stone pits have been removed through the sanding process.
Lacquer is the most popular as it dries faster (a few minutes)to the touch. But still takes a few hours to dry before it can be sanded prior to painting (70 degree dry weather).
Enamel is used as a 'sealer' which puts a block between the old or "prepaired" paint prior to application of the new (base coat)etc.
Epoxy is much harder after drying and can be left on quite a while after, before sanding, prior to the painting process.
None of these products (all good) are designed for, or to be used as; a "temporary paint job". They have specific uses as I have explained.
PLEASE get professional advice (a free estimate) from some one in the business before you attempt anything like this!!! It will save you a bundle of money and a whole lot of grief in the long run. BELIEVE IT.
A vehicle with an old paint job & a couple of 'dings'is far easyer to 'freshen up' than trying to fix a "do it yourself mess" and most shops will not even try.
Good luck to all, John M.....