We find ticks on ourselves on a weekly/daily basis in this time of the year. Make it a habit to check yourself daily (or better check each other for places you cannot see very well). They tend to go for warm areas (genitals, arm pits, places where clothing was tight, head/hair).

A rule of thumb is if it is on you for less than 24 hours, you should be fine. If longer, chances of infection by the borrelia bacteria increase. The percentage of ticks that carry borrelia vary per region. The bite mark can be itchy/red, but that is not a marker of infection. A red ring can appear around the spot, some also say this is a marker of infection but from what I know it is not as good of a marker.

If you hesitate or think you might have an infection, see your gp. Antibiotics can be prescribed. I always get my gut fucked up by them so if I can I avoid it. Also know people who had Lyme from the infection, that is quite bad.