1 month and half after breast reduction, I have a little pimple under my boob. Is it normal? (photos)

Everything was good, but this little white head showed up under my boob almost on the incision scar, and it had disappeared but now it came back and it's super painful. It doesn't look white or red anymore now it seems it's becoming a bruised pimple or so... what can I do? Is this normal? It wakes me up at night and it feels like the whole incision will rip open from the pain.