“Caturday hepped up on goofballs [after dental work] -> I was high on opiates on Saturday

Caturday -> Saturday

Hepped -> Novel synonym for “high” likely influenced by the jazz slang word ‘hep’ which means ‘hip’ or ‘cool’

Goofballs -> 5/500 hydrocodone/APAP, aka Vicodin. The gold standard tooth pain prescription drug, an opioid. In this context.

hepped could also just be "hopped" as in "hopped up on X" which is a relatively common phrase for being on some drugs or medication, but using kawaii speak which often softens vowel sounds, turning the open "ah" sound of the 'o' in hopped into a pronunciation of 'eh'. They couldve taken it further and said "hipped up" for no change in meaning. this may not have all been consciously decided, as many chronically online social circles use forms of this speech routinely and linguistics is a funny thing like that where the brain can adopt and make up things to fit it. May also be more of a 'fedora' speech pattern that younger online generation uses ironically in a nerdy voice (general ex. "m'lady"), hence the addition of trivial details like the version number and having early access to a new build of the game

always hard to tell exactly whats influencing the speech of the chronically online folk, but the mention of discord and well everything else about the post seem to strongly indicate it. all this to say, i doubt they were looking to be understood as much as they were just talking to talk and sending some in-group signaling