Stole this from one of TheAaron's older posts and it does work functionally. I am curious as to why it ouputs the gm:control portion twice to the chat window?
!token-mod {{ --set bar3_value|[[{@{target|Target|bar1}+2d4+2, @{target|Target|bar3|Max}d1}kl1]] --report all|"{name} takes a healing potion and regains {bar1_value:change}hp." gm:control|"{name} change: {bar1_value:before}hp -> {bar1_value}hp (+{bar1_value:before}hp)" --ids @{target|Target|token_id} }}