Absolution forgives the sin - it justifies us in the eyes of God - it forgives our dirtiness. Pennance helps scrub away the temporal effects of sin. Of course you should receive, unless explicitly told not to by your priest. Saying you shouldn’t receive until pennance is done is like saying you should work out 2x as much but not eat.
That said, not doing your pennance is evidence of a refusal to change which can constitute a mortal sin in of itself - so do the pennance ASAP
