2-3 weeks. Allergic contact dermatitis will resolve in 2-3 weeks if you continue to avoid the offending exposure.
I have allergic dermatitis. Last month during vacation sunbathed w/ one eczema w/ sunscreen. The rash is gone but the skin is lighter. Is it normal?
Yes. Sun exposure can decrease the severity of eczema. However, chronic exposure to the sun with or without sun burn can increase sun damage (not visible to the naked eye) and that can later lead to skin cancer. Ask your dermatologist or md for good moisturizer recommendations and for topical steroid oil or cream recommendations. This is safer that long term tanning for your eczema.
Not unexpected. It's called vitiligo and frequently follows allergic dermatitis or psoriasis. If it doesn't repigment see a dermatologist as there are psoralen and uv treatments.