A problem I've been having with Health Potions

Lately it's been impossible to punish the opposing player for mistakes and outplaying because of the fact that a single health potion will bring them from 1/4 hp (near death) to full hp.

  Now at level 1-2, we have a health pool of 600-700 depending and a health pot heals 185 max total (+20 from buscuit, +10% duration is another 1.5 seconds for another 15 hp).  There's a discrepancy of a lot of hp that people heal from, and the problem is that health pots don't heal me nearly as much.  After a level 1 to 2 harass / defense and my health is down low ~200, a single health pot leaves me a under 50% hp.  All the while the opposing player goes back to their turret (off of vision from enemy team), and when my health pot is done (same as theirs) they come back at full hp (no teleport) while I'm stuck at half, making engages much more costly for me.  Health regen runes are never used, I check lolnexus whenever this happens (to see what rune page they're running) and health regen items are not being used.

After the first back, if they come back with 3 potions there is absolutely no way to harass unless I kill them outright. I haven't been ranking this season because I've begun to notice this trend. It doesn't happen all the time, but it is happening often enough to where it would cost me too much in a game to consider ranking. Can someone explain wtf is going on? Been playing top lane since season 2 (last season plat 4) and I've never seen it this bad before.