AT 500 marks, getting a government medical college this year if you are from "GENERAL CATEGORY" looks difficult. 

As the paper level was easy comparatively this year and also the number of candidates haad rised, so the cutoff is expected to increase this year. 

Yes you can try in some private medical colleges of Kerala. The fee structure will vary from 6-9 lacs per annum and if you opt for a deemed university it may go up as high as 20 lacs per year. 

You can also try for BDS government colleges of Kerala. 

The state merit ranks once released, things will get easier and you will have a broad idea. Then the choice list forms will start after which you will need to wait for the first round.

Hope this helps. 

Best wishes.