Expert advice for Tretinoin
Do not take tretinoin and tell your doctor:

If you are allergic to tretinoin or any of the other ingredients or other ‘retinoid’ medicines (isotretinoin, acitretin and tazarotene) and peanuts or soya (as tretinoin medicines may contain soyabean oil).
If you are pregnant, planning to become pregnant or breastfeeding.
Do not drive or operate or drive machinery while you are taking tretinoin.
Avoid becoming pregnant during and within one month (four weeks) after stopping treatment with tretinoin. Consult your doctor for the right method of contraception you can use.
Avoid getting tretinoin cream in your eyes, nose, or mouth
Tretinoin cream may cause you to become sunburned more easily. Take suitable precautions (sun cream, clothing etc.).
Do not apply tretinoin cream to sunburned skin.
Do not stop using tretinoin if your skin condition appears to worsen for the first 2 to 3 weeks of treatment. This is expected. 
Talk with your doctor before you use any other medicines or products on your skin.
Tretinoin should be used extreme caution in children younger than 12 years old.

Q. Is Tretinoin a steroid/ retin a/ retin a/ a retinoid/retinol?
Tretinoin is not a steroid. It is a form of vitamin A (Retin-A) and belongs to a group of medicines called ‘retinoids'. Tretinoin and retinol are similar but Tretinoin tends to be a bit more aggressive than retinol which is a bit more suitable for those with sensitive skin

Q. Is Tretinoin safe/ Tretinoin cream safe?
Tretinoin is safe if taken at recommended doses and duration. The gel form should be used with extreme caution in children younger than 12 years

Q. Does Tretinoin cream work/ is Tretinoin cream good for acne/acne scars/ lighten skin/ thin the skin/ work on wrinkles/ fade dark spots/clog pores/ cause breakouts?
Tretinoin cream works effectively in most of the patients. It is useful for treating most of the skin related issue like acne, acne scars, skin lightening, removing wrinkles, fade dark spots, clog pores, etc. It does not cause breakouts but helps the skin in healing it

Q. Is Tretinoin available over the counter?
It is available only as per doctor's prescription

Q. Does Tretinoin stain clothes?
It may stain as it has a preservative in it.

Common Electrolyte imbalance, Redistribution/accumulation of body fat, Increased risk of infection, Bone degradation, Skin scar, Behavioural changes, Altered bone growth, Increased blood pressure, Muscle disorders, Increased glucose level in blood, Cataract.

Expert advice for Hydrocortisone
Do not use these medicine: 

if you are allergic to hydrocortisone or any of the other ingredients in this medicine.
on broken or infected skin.
on the face or near your eyes.
on the anal or genital areas.
if you are pregnant.

Do not apply plasters or dressings over the cream. Do not use on children under 10 years, unless your doctor tells you to. Do not use for a duration more than that is prescribed by your doctor, especially in children.
Do consult your doctor, if the skin condition does not improve after application at prescribed dose and duration. The injection can  may make you dizzy.
Do not drive, use machinery, or do any activity that requires alertness until you are sure you can perform such activities safely.The injection may mask signs of infection or put you at greater risk of developing very serious infections. Report to your doctor any injuries or signs of infection (e.g., persistent sore throat/cough/fever, pain during urination, muscle aches) that occur while using this medication or within 12 months after stopping it.

Q. Is hydrocortisone safe?
Hydrocortisone belongs to a class of medications called corticosteroids. Hydrocortisone is safe when used at prescribed dose and duration as advised by your doctor

Q. Is hydrocortisone same as cortisone, cort stim, cort s?
Cort s is proprietary (brand) name of hydrocortisone injection. Cortisone is other name of hydrocortisone. Cort stim is contracted (short) form for cortisol stimulation test

Q. Is hydrocortisone good for ringworm, cold sores, haemorrhoids, scars or burns?
No. Hydrocortisone is contraindicated in any condition where the skin is infected or inflamed

Q. Does hydrocortisone help in eczema, acne, hives, dry skin and thrush?
Hydrocortisone relieves the itching associated with eczema and local swelling and itching associated with hives. It should not be used in acne, dry skin and thrush

Q. Can I take ibuprofen, Tylenol or Benadryl with hydrocortisone?
NSAIDs like ibuprofen, Tylenol (acetaminophen), Benadryl (paracetamol, diphenhydramine, and phenylephrine) should not be taken if hydrocortisone is being taken orally. There is however little chance of interaction between hydrocortisone for local application and other drugs which are taken orally. Always follow the advice of the doctor regarding use of hydrocortisone ointment/cream and other medications.