two questions: are red spots on potatoes ok? white skin but purple insides

Two questions: are red spots on potatoes ok? White skin but purple insides; what kind are these?

Some white potatoes had red spots on them; they were starting to sprout. There were some without the red spots. 

At the time of cooking them a few days later, the potatoes were purple inside. The potatoes had white skins with purple insides.

There are two questions:

1. Do the red spots mean anything? Should you reject those potatoes?

2. Is that a different variety or are the potatoes bad?

Some deciding factors when choosing potatoes are that they don’t have green spots and don’t look shrunk. If they were starting to sprout on the red spots, you made a good choice in selecting others.

What is described as white skin and purple insides seems to be the Okinawan sweet potatoes.

Okinawan sweet potato

However, if you didn’t confuse them with sweet potatoes, that means that probably what you got is another variety of purple potatoes that I haven’t seen yet.