I wouldn't woory too much about doing damage. Subaru says you don't have to break the engine in due to very strict tolerances in the build of the engine. Doing a ~1000 mile break in is more of a preventive step. Most people here have done it including myself, but many have not also. General concensus here is that it is a good idea. Don't beat yourself up over it, just take it easy for awhile.