Maybe the start of Soolantra after some time off, could trigger a new temporary breakout, causing the second lesion. But could ofcourse also be unrelated to Soolantra.
I also wonder whether this time of the year (winter, with dry air and low humidity) could increase the risk of getting lesions.
The warning message could be for legal reasons. Soolantra/ivermectin is a medicine that is usually only available with a prescription. It probably cannot be sold legally for human usage without prescription, but for animals it can. So the manufacturer is maybe required to put such warning messages and animal logo's on the package.
But apart from that, Soolantra also warns about avoiding eye, mouth and inside the nose regions. A very liquid topical such as Catttle Pour-on could reach those regions more easily, which may be another reason for the warning. Also, the dose could be higher than tested on humans. And Soolantra probably has some kind of a patent for the usage of topical ivermectin on humans.
Some users here have used the oral form of ivermectin, but usually taken together with Soolantra, which makes it difficult to determine its efficiency. But looking at the known efficiency of Soolantra in other users here, and the possible side effects of oral ivermectin, I wouldn't try it unless Soolantra (and Sudocrem) have not much effect.
(Apart from oral ivermectin, oral metronidazole may also have similar effects, but is probably more serious in side effects.)