I'm wondering if this is a solution in search of a problem.
There isn't much point to casually browsing the site right now - I can see that someone else has achy feet, but I get no deeper insight; no comment explaining their situation nor comments from others that may have been similarly encumbered in the past.
Additionally, I only really share my health concerns with one person that isn't a doctor, and she lives with me.
The faces seem like a distraction when sharing anonymously. Many of them don't have an intuitive meaning, so I figure they're just for fun.
Also I couldn't figure out how to login or register on the site. I found out it's not actually required to share a health status, but since you listed it in the Show HN post, I looked around for it.
I do like the look and feel of the site - very straightforward and great colors, fonts, and design.
I wish I thought this were a good idea. Successful sites I have participated in started with being aimed at a particular diagnosis. I wish I thought this would work because it is clear to me that different diagnoses with symptoms in common often have related underlying causes. Unfortunately, this looks too nebulous to me. I hope I am wrong and I am routinely accused of erring in the opposite direction and making sites that are "too niche." But that's what it looks like to me.
PS Arguing with people who have given you feedback is not a great idea. It is a super common thing, but it really isn't a great idea.
Best of luck.
I love these guys. Was an early tester!
Links - Web - http://instawell.com
Docs - http://docs.instawellapiv1.apiary.io/
Blog - http://blog.instawell.com/post/53509254012/public-api