The Seal of the Prophethood, which was essentially a mark etched into the pure skin on the blessed back of our beloved Prophet Muhammad (Allah’s peace and blessings be upon him), has been described differently in various hadeeths.
This is because there was nothing exactly like it in the world to compare it to: only the Final Messenger (Allah’s peace and blessings be upon him) bore this sign, so that those of knowledge could identify him without a shadow of a doubt.
Hence, each Companion would describe it as he saw it, trying his best and using relative descriptions that would help us imagine what it must have been like. So the differences you read about in hadeeth accounts are not problematic: they are relative perspectives.
...
https://www.youtube.com/watch?v=UdDz98wEurc