Two things come to my attention.

The first is that your growing them in a pot. If you've done that in the past with success then we can move on to the second thing.

The second thing is blisters on the stem of your plant.Bacterial Canker disease will cause blistering on the stems.

If now your thinking its more likely the second. I don't have much to offer. I've only read about it. I suggest you do a google search on it until someone else can reply.

If you havn't grown tomatoes in a pot before reply back with as much info about how your going about it i.e. pot size, soil, watering method fertization ect..

Post a picture if you can.

Now, my blossoms are dying/wilting soon after opening, the stalks have what appear to be blisters and now, the only fruit I have(2) which are about the size of golf balls have become black on the bottom side. My plants are in pots, full sun and caged. Any suggestions would be greatly appreciated. Thank you

Blossoms dying/falling off is called blossom drop and is quite normal when conditions are present for that to happen. Go to the main tomato Forum, link at the top of this page and when there, click on the FAQ area at the top and look for the blurb on Blossom Drop.

Blisters on the stems? What color? If kind of whitish looking and spikey they are root primordia and normal, if they are a darker color and flat they could indicate many things depending on where else on the plants you might see symptoms.

The black on the bottom of your fruits is probably blossom end rot, BER, and there's also a FAQ in the main tomato forum about that.

I'm also assuming that the mix you put in the pots was not native soil. RIght?

Carolyn