The documentation of ethnopharmaceutical knowledge has always been important for the preservation of countries’ cultural, social, and economic identity. The COVID-19 pandemic with the collapse of healthcare, which has left the individual health to self-care, has also forced us to look back at ethnopharmacology from a practical point of view. This is the first study in Lithuania, dedicated entirely to ethnopharmaceuticals used for skin diseases and cosmetics, and the first study to analyse ethnopharmacology as a Lithuanian phenomenon during the ongoing COVID-19 pandemic. The main purpose of this study was to collect and evaluate ethnopharmaceutical knowledge regarding skin diseases and cosmetics in Šiauliai District, Lithuania during the COVID-19 pandemic from July 2020 to October 2021. This study surveyed 50 respondents; the survey was conducted using the deep interview method. The respondents mentioned 67 species of medicinal plants from 37 different families used for skin diseases (64.18%), cosmetics (13.44%) and cosmeceuticals (22.38%). Of the 67 plant species, 43 (64%) were not included in the European Medicines Agency monographs and only 14 species (21%) of all included species were used with European Medicines Agency approved medical indications for skin diseases. In terms of public health, the safety of “self-treatment” and recovery rituals for skin diseases are no less important than ethnopharmacological knowledge and its application, this being especially relevant during the COVID-19 pandemic.