Age spots

Hello,  sounds like hyperpigmentation and yes chemo can cause it.  Another skin condition that can look like hyperpigmentation is melasma.  Have you gotten a diagnosis yet as treatments differ.  There is an excellent dermatologist on YouTube and her channel is Dr Dray.  She talks about skin issues with chemo, hyperpigmentation etc.  The information should be helpful. Very important to wear sunscreen everyday.  I live in Florida so a real must for me as I would be red as a lobster.  
Take care and hugs to you and you will be able to manage your skin issues with consistency.

I have them in summer on my hands which Sidmouth started after chemo and hormone blockers.  They fade in the winter. 

 I always use sun screen on my face but brown  marks appeared above my mouth approx 9 wks into chemo.

I do think it's due to chemo rather than age related. I'm hoping they will fade after a while.

Thank you, that's interesting. I'll have a look at Dr Dray's channel

I may not start using more sunscreen when it gets warm. I never usually burn and didn’t use to bother unless I’m on holiday. 

Sunscreen is the best anti aging thing you can do for your skin.  I have gotten into the habit of using it everyday after I wash my face and also put it on my neck too.  Live in hot and sunny Florida and I am a paler skin type.  Wear a hat too most of the time when I go outside.  I had sunburns as a child as the only tanning cream was copper tone and I think the spf was maybe 2 or 3.  Ugh!!