Is a wound turning yellow without pus okay?

[GrumpyPumpkins]

About three days ago I was working on something with an exacto knife (brand new, only used on plastic prior to the incident) and I lost my grip and it stuck my inner thigh. It definitely went in a bit because there was a lot of blood. I applied pressure and it stopped bleeding after a few minutes and then applied alcohol and bandaged it up. I kept on cleaning it throughout the next day with rubbing alcohol, but I only started putting neosporin yesterday because I never get cuts and I stupidly didn't think to pick some up until yesterday. I woke up this morning and now the wound area is all yellow. There area directly around the wound is red, but it hasn't spread or anything. It doesn't hurt to touch it, there's no pus, and it looks like the little bit of red that's directly around the wound has become a bit more "flesh" colored, so to speak.

Why did the wound all of a sudden become yellow three days after the incident? It looks bruised, almost. Is this my white blood cells fighting whatever did get through when it happened?

I'm a terrible hypochondriac and have the worst emetophobia out of anyone you'll ever meet, so I might just be making a big fuss over nothing, but I'm truly terrified of getting a fever (which I know is common with wound infections) or having to take antibiotics (that make you nauseated).

Any insight into the situation would be helpful.

Thanks!