Changing Google Play country: Are there any side-effects when it comes to available apps?
I did this when I moved across countries - the apps are unaffected. If you had apps which are available in the earlier country then you can continue updating and using them. The only downside is that if you have credit in your account, then that doesn't appear in the new country. You can still use the credit if you change your play store country back to the old one.