Yeah, nothing is perfect. You may try different settings on snapping (these parameters under project palette).
You may try subdivide once/project, a second subdivision/project again and so on. Just remember to say no to zb when trying to transfer polypaint. Only when you reach >2M then say yes. You get the idea? You need hi def to capture paint.
You may try smoothing once these spikes happen. It's not so easy, I know. But try to think this way. Have you tried to work with real clay, rubber, plater (gypsum)? Some similar difficulties LOL
Please check the retopo cage in this area, something wrong there?
Let's say you managed all this (you will), so what's next? To UV it. An endless torture LOL, I told you I have some talent on this.

Then what? To bake textures and export. Oh my.
Then what? To render on another app-renderer. ha
It's not endless.
Oh, I forgot it, you may like to rig it, to go for animation. This is the end of all this procedure. Not that bad, One at a time. And have fun.