Playing guitar leaves indents and blisters in my fingers?

Whenever I play the guitar, it always leaves depressions in the shape of the strings, and sometimes even blisters.

I don't play for long, just fifteen minutes or so. I've been playing for a few months, so I expected my fingers to toughen up by now. But they haven't…

I especially suck at bar chords. Those seem to strain my fingers the most.

Any help?

you'll get used to it.
im guessing you play acoustic?