If I remember correctly on older Honda civics at least (90% f the Integra is a civic in design and parts are usually interchangeable or sometimes identical), the intake manifold comes over the valve cover so it'll be a 2 hour job if you know nothing about it and it'll be your first time tackling such a procedure.
As for damage or whatnot, not much. You might lose some oil between oil changes, anywhere from negligible to maybe 1/2 a qt but nothing really all that bad. The main thing to look for is if you need to change the PCV valve also. It's possible crankcase pressure built up and pushed the gasket out and the PCV valve is a maintainence item that needs replacement if it clogs. Again, not a big deal, a PCV valve is cheap and decently easy to replace. Get a shop manual and the 2 repairs will be relatively as painless and easy as it gets as far as working under the hood goes.