The manufacturer of the drug does not mention the occurrence of any side effects on the digestive system after using Tetracyclinum ointment.

Only the side effects listed in the SPC (Formulation Characteristics) concern the skin and subcutaneous tissue as a result of the local action of the ointment.

Side effects that may occur after oral use of tetracyclines are gastrointestinal ailments, such as nausea, loose stools, diarrhea. They are usually mild and often resolve during or after treatment.

Therefore, if you have symptoms of the digestive system after applying the ointment topically to the wound, you should observe the stool. If the symptoms do not disappear within a few days or even intensify, I would advise you to contact a doctor.

A light color of the stool or yellow color may result from a lower or negligible content of bile produced in the liver, which has entered the digestive tract or from excessive fat content. Pus that is an admixture of stool may also have a yellowish color.

If you are unable to contact your doctor, you can use the teleconsultation here:

https://www.gdziepolek.pl/telekonsultacja

In the meantime, I encourage you to report this symptom as an adverse reaction.
We wrote more about how to do it and why it is worth it in this article:

https://www.gdziepolek.pl/artykuly/jak-i-dlaczego-zglaszac-dzialania-niepozadane

Here you can check the availability of the drug with the possibility of reserving it at the pharmacy: 

https://www.gdziepolek.pl/produkty/78288/tetracyclinum-3-masc/apteki