Please choose the correct ending to complete the given sentence: Education and Communications: [header] How to treat a hydrofluoric acid burn [title] Recognize the effects of hydrofluoric acid. [step] Hydrofluoric acid (hf) contact with skin can cause severe chemical burns. Direct contact with hf can cause major damage to your skin tissue, as hf is a corrosive substance that burns.

Ending1: If you are trying to treat an hf burn at home, talk to your doctor before proceeding to handle it. [substeps] An hf burn is caused by the trapped chemical co2 in the body. Ending2: It can also penetrate the skin and cause even further damage under the skin. [substeps] This can be even worse, depending on the concentration of the acid and the length of exposure. Ending3: The reactions that occur can cause both skin damage and negative consequences for your skin. [substeps] Hf injections also cause symptoms that are unusual and potentially serious, like skin blisters, rashes, and boils. Ending4: Avoid direct contact with hf after a sore or achy burn, as your skin might soften in response. Do not use hf to treat an injured wart, or you could develop another burn.

Answer format: ending1/ending2/ending3/ending4