Contact Dermatitis: This is the most likely diagnosis due to the direct exposure to chemicals, which can cause an allergic or irritant reaction leading to skin swelling, redness, and itching.

Chemical Burns: Exposure to certain chemicals can cause burns, leading to skin swelling, blisters, and pain. The severity can vary depending on the chemical and the duration of exposure.
Irritant Contact Dermatitis: Similar to contact dermatitis but typically caused by a non-allergic reaction to substances like acids, bases, or other corrosive materials.
Allergic Contact Dermatitis: An allergic reaction to specific substances that come into contact with the skin, leading to swelling, redness, and blistering.

Anaphylaxis: Although rare, anaphylaxis is a severe, life-threatening allergic reaction that can occur after exposure to certain chemicals. It requires immediate medical attention.
Toxic Epidermal Necrolysis (TEN): A severe skin condition usually triggered by medications but can also be caused by chemical exposure, leading to widespread skin necrosis and detachment.
Stevens-Johnson Syndrome (SJS): A rare but serious disorder of the skin and mucous membranes, often caused by an adverse reaction to medication or infection, but can also be triggered by chemical exposure.

Erythema Multiforme: A skin condition characterized by target lesions, which can be triggered by various factors including chemical exposure, though it's more commonly associated with infections and medications.
Fixed Drug Eruption (FDE) or Chemical Eruption: A type of skin reaction that occurs at the same site every time the particular chemical or drug is taken or exposed to.
Phytocontact Dermatitis: A type of contact dermatitis caused by plants, which can sometimes be considered under chemical exposure due to the plant's chemical composition.