Great shot but your explanation as to why it's blown out is a little backwards. High ISO by itself doesn't cause over-exposure; you could have used the same ISO but with a shorter exposure or smaller aperature and it wouldn't have been blown out.
The problems with high ISO are more noise and less dynamic range. It is better to use a lower ISO whenever possible, which is hard to do with astrophotography though.
I look forward to seeing your Milky Way photos