boot

[Over the top]

blushing at anything and everything messes up your social life and can really put the boot in to your career aspirations

Does 'put the boot in' mean to end? Can you give another example where this phrase is used?

[freezeframe]

Does 'put the boot in' mean to end? Can you give another example where this phrase is used?

That must be BrE because I've never heard that phrase before.

[Over the top]

I found it in a blog. I imagined putting the boot in is to kick

[freezeframe]

Reminds me of the timeless Father Ted episode, "Kicking Bishop Brennan up the Arse". Very sophisticated British humour -- highly recommended.

[JMurray]

over the top.
To "put the boot in" is quite a common phrase here and is almost invariably used figuratively, meaning to attack somebody vigorously either verbally or in writing, or in a political cartoon for example. It is often used in a situation where an attack has been made and then followed up with another one, and so can have a similar meaning to "kicking someone while they are down".
The example you give, which is about damaging your own career rather than a person, is a little unusual but wouldn't sound too strange in conversation, or indeed a blog.

not a teacher