I honestly don't think this is a big deal, especially since the longest race is last.
Unless this is the very end of your training cycle or season, I would still try to get in one long run each week and one faster day of either tempo or intervals. That assumes that you follow the standard approach of one long run, one tempo effort and one track session (or its equivalent) most weeks. Simply sub the races in for an intense training day.
I find it interesting that runners today view racing differently than they did 25 years ago. In college in the early 90s, we probably raced close to 20-30 times a school year (8-10 races per season for each of xc, indoors and outdoors, although outdoors was often a little on the short side). We still got in a track session, a tempo session and a long run in addition to our races; but all races were treated as important, and none were run "just as a workout." I am not saying that this is right or better or anything, just noting the distinct change in perspective and direction over the last couple of decades.