How would I know if the cut is closed

[Bommo1234]

Ok I posted a question the other day describing a cut that I had. My cat scratched me on Tuesday and its about an inch long and so small in diameter that I can't give an estimate of measure, it wasn't very deep and bled for a very short time. I cleaned it with alcohol  after it happened and kept it covered until yesterday(Friday). That's all I did. I was wondering if there was an entrance into my blood stream for viruses, bacteria, etc. people said as long as it scabbed and its closed, there's no entrance. How do I know if a scab has formed and it's closed. Like part of it is like dark reddish and clearly a scab. The other part is brown and it's so small I just can't tell if it's closed. Even though I can't really show you a picture:
1) how would I know if it's formed a scab and closed
2) would a scratch this minor normally be closed by now