Asking an external professor for a feedback on my BSc. thesis In my senior year. I have put so much effort in writing my thesis and my supervisor didn't even read what I have done or even bothered to do his work, I wrote my thesis in a topic in mathematical analysis. I think it is interesting to read, no new results but, there are many undergraduate publications that are just interesting to read and contains no new mathematics! so I think my thesis is interesting to read.
All undergraduate journals I found requires a letter from the supervisor, I can't get a letter from him because:
1. He didn't read it and he won't 
2. My relationship with him is not good

I thought maybe I should ask an external professor to give me a feedback but, who would do that!
I am even embarrassed to ask for such a favour. I just want to learn even if my thesis is not as good as I think it is, it is okay but at least I would then know why and learn something!

If I had it published. It would then help me when I try to apply for scholarships and stuff.

Can someone suggest me a solution or something? 
Do other professors normally agree to review other student's work?

Thank you.
Look for other magazines that don't require such a letter.  (Do they all?)
Find a professor that you can talk to. Or a postdoc.  Or a visiting scholar.  Some won't give you time of day, but some will be OK for a conversation.  Then maybe talk about what you've done that was interesting.  (Make some notecards and then be able to show/talk about the topics on the board.)  Keep it a little lighter than "read my manuscript".  That's a little leaden to be expected to read amateur work.  But a meeting where you are able to say interesting things like 

"lots of people want to have geometric interpretations of analysis and say that is novel, but they most likely think in areas or volumes.  I like to think in decision trees and nodes.  It's not really novel, as Russian authors from the 50s like Guestanovitch have written this way.  But it's kind of rarely seen nowadays."

[Made up example...I don't know analysis...but you get the drift.