If your Python environment seems to be buggy or broken after a recent Python upgrade, it probably is. To fix it, simply execute the following command on your Gentoo box:
# python-updater -v
(note that this process takes quite some time to complete)
Additionally, you might want to make Gentoo check the dependency tree and rebuild broken packages (related to Python or other packages):
# revdep-rebuild
P.S. This is more or less a repost of an earlier post about python-updater.