Probably not, at least for practical purposes. A lens produces the strongest heating only near the point where light comes to focus, and that usually is not inside the lens itself. Also, lens elements are designed to transmit most light rather than absorb it; if they absorbed a lot of energy, they would perform poorly as optics. That makes internal heat damage from briefly using the lens as a burning glass unlikely.

Based on the descriptions and photos, it is more likely that the mark was already inside the lens and only became noticeable because you inspected it very closely under directional light. Small internal dust, fibers, or minor imperfections can show up this way and often have no visible effect on image quality.

If the lens still focuses normally and your photos look unchanged, there is little reason to worry. If you want peace of mind, compare images against earlier ones or have a technician inspect/clean it, but the evidence here points more toward a harmless internal speck than burn damage.