Mistress's Punishment Session

I've been in my transition for about two years now and have recently begun exploring a kinkier side of myself through Dominant/Submissive dynamics with a woman I'll call 'M'. She's around 30, much more experienced than me. We started our D/s relationship last month after an intense roleplay session where she took on the role of my strict mistress. Initially, it was exhilarating and empowering for me to be dominated, but there were moments that felt a bit too real and intense. M has this thing where if I don't follow her rules perfectly, she punishes me physically. She uses a flogger which really stings when hit against my back or buttocks. We've agreed on safety limits, no breaking the skin, and to use painkillers after sessions as needed. But today was different. I messed up in our household chores roleplay this morning by not waking up early enough for her liking. I felt embarrassed and tried to make excuses, but M cut me off. She told me firmly that my punishment would be a longer session than usual. I swallowed hard as she brought out the flogger, her expression cold yet calculating. The initial swats were sharp stings against my bare skin, leaving welts and a fiery sensation pulsating across my backside. My body tensed up with each strike, trying to avoid the pain but knowing it was inevitable. M's hand movements became faster, hitting harder in spots that I couldn't shield properly. My eyes watered from the stinging, but I bit back any cries or pleas. When she finally stopped after what felt like forever, I collapsed onto the bed, my skin burning and aching fiercely. She calmly ordered me to take a cold shower immediately to soothe it. The biting chill of the water against the red welts was nearly as painful, but it helped numb them somewhat. Afterwards, we talked things through. M explained that sometimes pushing boundaries is necessary for growth in this dynamic and asked how I felt about today's session. Reflecting on it now, while my body still hurts physically, there's a strange sense of satisfaction mixed with unease knowing I'm walking the edge between pain and pleasure. It’s new territory for me, but I’m intrigued by what might come next.