If I were to use a move like Ingrain (for example), and then three turns later my opponent used Heal Block.
No. This is a passive healing move, and Heal Block only blocks direct healing moves, or most commonly called, "Reliable recoveries." Attacks like Aqua Ring and Ingrain are not blocked by Heal Block, as far as I know.
You would not get any healing.
Source: Testing
As you can see, my Ferrothorn was not gaining any heatlh back.
