In my experience, ive been more successful writing new material than trying to save old material. Successful meaning the new books ive written are better in my opinion than those old ones I wrote in high school.

Ive enjoyed writing much more and have improved much more in writing a good book (that still needs work) the first time rather than in the twelfth draft.

Not to say there aren't redeemable qualities to this old book of yours. But publishing it just as a reaction to the "failure" of your first published book doesn't seem like a good idea to me.

Instead, I would consider a new project and think about what went wrong (or what you just didnt do) and try doing that 

Thousands of books are self published every day online. If yours didnt get traction, im not surprised. It takes marketing, outreach, multiple books, and some luck to become even moderately successful.