Some (Chinese) Life Hacks

Mosquito bites
Apply white vinegar on afflicted area. Vinegar neutralises the toxins that cause swelling and itching. The reddish bump should disappear in 10-20 minutes.
(Tried and proven.)

Bruises
Rub a (peeled) boiled egg repeatedly over bruised area. By magic, black spots will appear in the egg and bruising should reduce.
(I don't know how this works... This is something our mamas told us.) (By our, I mean me and my Chinese friends.)

Pimples
Use saline solutions to gently wipe your face (with cotton or a towel). It cleans better than pure water.
(Grandma wisdom.)

Wounds 
Buy hydrocolloid dressing, for example here, by DuoDERM. The dressing is a biodegradable and non-breathable (aka waterproof) type of plaster that you paste over more serious wounds. The dressing absorbs liquid and keeps the wound moist, but not wet, which facilitates healing.
(Tried and tested. Works amazing. My mom buys a lot of these every time we go to Taiwan. They're called 人工皮 in Chinese.)

Get rid of odours
Buy legit dried tea leaves (any type will do). Place them, dry, in places with odour such as shoes, water bottles, refrigerators... Or you could just make tea in your bottles and leave them overnight. The tea leaves get rid of the nasty odours plus they leave the nice tea smell behind. Lemon skins work too.
(Mom hacks.)

Mouthwash
Instead of buying commercial mouthwash that leave burning sensations, use salt water to rinse your mouth. Really salty water. Add as much salt as you want to water and rinse for about 5 minutes. Salt is a great bacteria killer. Please do not swallow the water.
(Mom hacks.)

Mouth Ulcers
Quick ways to get rid of ulcers:
1. Put salt on it. Immediate effect, but also extreme pain. Warning: ulcer may bleed.
2. Citrullus Degelatinatum/ Watermelon Frost(?) (西瓜霜). Get it at a local pharmacy. Medium effect, but not as painful. Have to reapply (I do it twice a day, but it's okay to use more).
(Mom hacks.)

Mosquito Repellent
Sesame oil. Mosquitos hate sesame oil. Dab some all over your skin and you should be rid of mosquitos for a while. Downside: you smell like 麻油鸡 (sesame oil chicken dish) in the meantime.
(Mom hacks.)