There is no face saving option for Putin at this point. He's far too overcommitted and nearing a point where EU and NATO are beginning to see cracks in his hold on power. In his own mind, his only out in all of this will be to take Ukraine by going ultra-violent. Anything else will be considered a weak capitulation involving him ruining the Russian economy while returning from Ukraine empty handed. Also, now that the international community has him in a weakened position, they aren't likely to remove the sanctions until he pays for the damage and destruction in Ukraine and signs an agreement to fund its reconstruction. He of course, isn't going to agree to any of these things and is incentivized to double down on taking Ukraine.