"Self absorb that pity I want to
Knock you off your horse"
The person should feel sorry for themself (or ask for pity on them) - not the writer
"Take your medicine like a champ"
as in the saying "a taste of your own medicine" - it's probably payback or revenge for something.
"While that sting can last a million years"
The sting that he felt caused by this person, he knows it lasts a long time and he's giving it back to them.
"Self absorb that utopia, so bad, I just feel it"
This could be something like whatever the reason is that the person thought they were so good(or whatever their "utopia" was), it's faling away and now the writer feels it.
"Self absorb that pity I want to Knock you off your horse" The person should feel sorry for themself (or ask for pity on them) - not the writer
"Take your medicine like a champ" as in the saying "a taste of your own medicine" - it's probably payback or revenge for something.
"While that sting can last a million years" The sting that he felt caused by this person, he knows it lasts a long time and he's giving it back to them.
"Self absorb that utopia, so bad, I just feel it" This could be something like whatever the reason is that the person thought they were so good(or whatever their "utopia" was), it's faling away and now the writer feels it.