Hi Umm Well Yesterday I Was Attacked But Another Person

hi umm well yesterday I was attacked but another person and they hit my head with a bear spray can and I have a huge gash on my head paramedics said I didn't need stitches but its pussing and my boyfriend told me that's when theres so much bacteria in the gash that its pushing the bacteria out should I be worried if I don't treat it ? and if I do need to treat it what is the most less painful thing to treat it with ?