Okay so just to get this straight. In the mini comics, Keldor had a kid with Evil-Lyn before he had acid thrown on him and sometime before after becoming Skeletor Evil-Lyn hid said baby. But does Skeletor even remember the kid?
The event your talking about happened specifically in the Classics-line comics. The mini-comics that were published in the 2010s and came with the Classics toys. This was Skeleteen's first appearance in a MotU media that made it through production. Previously, Skeleteen had only ever been a "concept character" and never made it past the concept phase.
(I have to add disclaimers like that now because there's an Anon out there who is apparently very offended when people mix canons.)
Yes. Keldor and Evil-Lyn had a baby together. Then, when Evil-Lyn saw the way Keldor changed after he became Skeletor, she feared for her child's safety and handed the baby over to Mighty Spector.
It's unclear whether or not Skeletor remembers that he had a kid. It never comes up again Skeletor is already dead and Skeleteen returns as an enemy working under the command of the Unnamed One.